What happens when Blueworx Voice Response receives a call?

When Blueworx Voice Response receives a call over Voice over IP, a specific sequence of events is followed:

1. Blueworx Voice Response receives a SIP signaling sequence (beginning with an INVITE message) which is processed by the SIP stack and passed on to the SIP signaling process within the VoIP-SIP signaling process.
2. The SIP signaling process informs Blueworx Voice Response that an incoming call is in progress.
3. Blueworx Voice Response parses the URI and looks to see if the 'user' part contains a valid E.164 telephone number; if it does, this number is used as the calling number and Blueworx Voice Response tries to match the number to an application (State Table, Java, CCXML or VoiceXML). If a match is found Blueworx Voice Response launches the application on the channel receiving the call. If no number is available, one of the following is used as the calling number:
   • The default number of Blueworx Voice Response
   • The default application number for all SIP channels is configured in the Channel Identification window which is displayed from the Pack Configuration window by clicking on the Channel IDs button for a Pack. Refer to the Blueworx Voice Response for AIX: Configuring the System information for details.
4. When Blueworx Voice Response connects the call it sends a command to the DTNA to start streaming voice (RTP) in both directions.
5. The DTNA converts the continuous voice stream into RTP packets to be sent across the network. Packets of voice data that arrive from the network are received by the DTNA, put into order and converted into a continuous voice stream, which is passed to the ‘core’ of Blueworx Voice Response.
6. When the call is ended the signaling process sends or receives signaling information (depending on whether the call was ended by near-end or far-end hang up) and the voice streaming is stopped.

Outgoing calls operate in a very similar way to inbound except that the initial signaling is sent from the Blueworx Voice Response signaling process to a User Agent Server (UAS) (usually through a SIP proxy server).