The information in this document is based on these software versions:
CVP Server 9.0(1)
Voice XML (VXML) gateway
Cisco Unified Border Element (CUBE)
Cisco Unified Communication Manager (CUCM)
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Courtesy callback is not offered, when Estimated Wait Time (EWT) in the ICM is set more than 30 minutes.
Consider this scenario:
When a caller makes a call, a callback is offered and accepted. The callback is initiated and the caller answers the call. After 250-260 sec the callback entry on the Reporting Server portal gets erased and as a result no Courtesy Callback is offered.
When EWT in the ICM is set more than 30 minutes, the callback entry on the Reporting Server gets erased and as a result the Courtesy Callback is not offered. This is because the Gateway terminates the VRU leg by sending BYE which Unified CVP uses for any callback. As a result, Unified CVP erases all call details of the call and as result the callback is not made. It is found that a possible SIP session time out causes this behavior.
This configuration has to be made on the Ingress gateway/CUBE:
voice service voip
min-se 7200 session-expires 7200
Note: In addition to the above configuration, the session expire in the CUCM should also be changed to a higher value (7200), otherwise the callback fails in Unified CVP due to SIP error response 422(session expire value too low) from Gateway.