When SIP
                                 		is used, the significant digits are prepended to the DNIS number, and a SIP
                                 		Proxy can be configured to route calls based on those prepended digits. The
                                 		static routes in the SIP Proxy for the VoiceXML Gateway should have the digits
                                 		prepended. Because these prepended digits were originally populated by the
                                 		Ingress Gateway, the SIP Proxy can use them to determine which VoiceXML Gateway
                                 		to use based on the incoming gateway. In this way, calls arriving at a
                                 		particular site can always be sent back to VoiceXML treatment, with the result
                                 		that no WAN bandwidth is used to carry the voice RTP stream. The Unified CVP
                                 		indiscriminately prepends the 
                                 		sigdigits
                                 		value to all transfers, including those to UnifiedCM. Therefore, when using
                                 		UnifiedCM in this scenario, it is necessary to strip the prepended digits when
                                 		the call arrives, so that the real DNIS number of the phone can be used by
                                 		UnifiedCM to route the call, as illustrated in the following example. 
                                 	 
                              
                              
                                 
                                      Note | 
                                    
                                       
                                           
                                          		
                                          The configurations mentioned below are only applicable to IOS Voice
                                             		  Gateway. 
                                             		
                                           
                                          	 
                                           
                                       
                                     | 
                                 
                              
                              Configuration of Ingress Voice Gateway: 
                                 	 
                              
                              Apply a
                                 		translation rule to the incoming DNIS to prepend the value 3333: 
                                 	 
                              
                               
                                 		      translation-rule 99 
       rule 1 8002324444 33338002324444
      dial-peer voice 1000 voip
       translate-outgoing called 99
 
                                 	 
                              Assuming
                                 		the DNIS number is 8002324444, the final DNIS string routed to Unified CVP is
                                 		33338002324444. 
                                 	 
                              
                              Configuration of Unified CVP SIP service: 
                                 	 
                              
                              To
                                 		configure the SIP service, in the Operations Console, select 
                                 		Call Server >
                                    		  SIP. Many of the settings are in the Advanced Configuration window. 
                                 	 
                              
                              Configuration of 
                                    		  IOS VoiceXML
                                    		  Gateway: 
                                 	 
                              
                              Configure
                                 		the Voice XML Gateway to match the DNIS string, including the prepended digits:
                                 		
                                 	 
                              
                               
                                 		      dial-peer voice 3000 voip 
       incoming-called number 33335551000T
       service bootstrap
       ... 
 
                                 	 
                              Configure
                                 		the Unified CVP bootstrap.tcl application with the 
                                 		sigdigits
                                 		parameter, indicating how many digits to strip off of the incoming DNIS string:
                                 		
                                 	 
                              
                               
                                 		      application 
       service bootstrap flash:bootstrap.tcl
       param sigdigits 4
       ... 
 
                                 	 
                              Cisco
                                    		  UnifiedCM configuration (if used): 
                                 	 
                              
                              Configure
                                 		UnifiedCM to strip the prepended digits, either by using the Significant
                                 		Digits configuration on the SIP Trunk configuration page or by using
                                 		translation patterns. 
                                 	 
                              
                              SIP Proxy
                                    		  configuration: 
                                 	 
                              
                              Define
                                 		static routes on the SIP Proxy, with the prepended digit present, to be sent to
                                 		the appropriate VoiceXML Gateway. Because transfers to agents on a UnifiedCM
                                 		cluster have prepended digits, the static routes for agent phones must also
                                 		contain the prepended digits. 
                                 	 
                              
                              Summary
                                    		  of call routing: 
                                 	 
                              
                              
                                 -  
                                    		  
                                    
A call arrives
                                       			 at Unified CVP with a DNIS number of 33338002324444. 
                                       		  
                                    
 
                                    		
                                  
                                 -  
                                    		  
                                    
Unified CVP
                                       			 removes four digits (3333) from the beginning of the DNIS string, leaving
                                       			 8002324444. 
                                       		  
                                    
 
                                    		
                                  
                                 -  
                                    		  
                                    
The number
                                       			 8002324444 is passed to ICM for call routing. 
                                       		  
                                    
 
                                    		
                                  
                                 -  
                                    		  
                                    
When it is time
                                       			 to transfer, ICM returns the label 5551000102. Unified CVP prepends 3333,
                                       			 resulting 33335551000102. 
                                       		  
                                    
 
                                    		
                                  
                                 -  
                                    		  
                                    
The SIP Service
                                       			 then resolves the address using the SIP Proxy or local static routes, and it
                                       			 sends the call to the VoiceXML Gateway. 
                                       		  
                                    
 
                                    		
                                  
                                 -  
                                    		  
                                    
The VoiceXML
                                       			 Gateway bootstrap.tcl removes 3333, leaving 5551000102 for the destination
                                       			 address.