Sample 3 In-band Ringback without Alerting Message

This sample flow shows how the Oracle® Enterprise Session Border Controller handles a call that requires the IWF where there is no progress message. In this call flow, there is a progress indicator of eight (8), meaning that ringback is in-band.

In this diagram, you can see that the Oracle® Enterprise Session Border Controller maps the progress indicator included in the Progress message sent from Phone 1 through H.323 GW2 to a SIP 180 message with SDP. When the Alerting message appears, it contains the progress indicator rather than the Progress message containing it.