Host Control Method of SIP 180 Provisional Response Generation
Prior to this feature, the CSP delivered a SIP 180 Ringing Response to the calling SIP endpoint as a result of the host application sending a Park Channel or Connect message. At its discretion, the host application could initiate the 180 Response by sending a Park Channel message to the calling endpoint’s span/channel at any time prior to issuing the Connect message. If the Park Channel message was not sent and the host application issued the Connect message, the CSP automatically generated the 180 Response after receiving alerting or an answer from the called party. In either case, the CSP always sent a 180 Ringing response to the SIP calling endpoint.
With the Host Control Method of SIP 180 Provisional Response Generation feature, developers can use the Alerting Propagation Mode TLV (0x0117) in the 0x1E PPL Generic ICB in the following messages. Sending this TLV prevents the CSP from automatically generating the 180 Response to the calling SIP endpoint.
• PPL Event Request for Answer in L4 CH component
• Connect with Data (0x0005) message
API Messages Used
• PPL Event Request (0x0044)
• Connect with Data (0x0005)
The following call flow shows the SIP 180 Provisional Response Generation feature in an environment with a Voice Recognition Unit (VRU). Note that the SIP 180 response is suppressed for this call.