Cisco Cisco Customer Voice Portal 8.0(1)

abnormal disconnect even though the Unified CVP survivability script on the ingress gateway
might detect this event.

How Critical Error Message Playback Works

Critical Error Message playback works as follows:

•

For typical TDM calls using the survivability service on the IOS Gateway, the error message
is played using the survivability script when it detects the non-normal disconnect code after
Unified CVP has disconnected the call (refer to SIP BYE message). The display name of
"--CVP" is appended in a Remote Party ID header of the SIP call. This is how the SIP Service
can identify whether or not the incoming call uses survivability. For example, IP-originated
Cisco Unified Communications Manager callers will not have this setting. All TDM callers
must have survivability service.

•

For IP-originated calls that the SIP Service detects is not using the survivability service,
when the call is disconnected and the reason code is abnormal, Unified CVP sends a REFER
message with the SIP URL of the error DN. The error DN must be configured in the dial
plan to point to an IOS gateway that has the cvp-error TCL service configured. When the
caller gets the REFER TO destination, it attempts to blind transfer the call to the Unified
CVP Error service on the gateway. Once Unified CVP sends a REFER for error message
playback, it cannot retrieve the call, so it is important to confirm this mechanism is configured
correctly during deployment. For any call that Unified CVP sees is not using the survivability
service, it will attempt the REFER method to the error DN for critical error message playback
for abnormal disconnects.

•

For third party SIP gateways, where the survivability service is not running, and you desire
to avoid the use of the SIP REFER to error service, it may be turned off in the SIP section
of the Call Server configuration. Turning off this property allows Unified CVP to pass through
the rejection response as-is to the caller, or else the BYE with reason header will be passed,
depending on the call state. It may be that the SIP gateway does not implement SIP REFER
and you desire to turn this setting off.

Delivering SIP Incoming UUI to Unified ICME Routing Script

For SIP Calls, ISDN call parameters such as "user to user information" (also known as "UUI"
or "UUS") can be passed to the Unified ICME script. (ISDN call data is only forwarded in SIP
calls from the TDM calls using a gateway.) On the gateway, the "signaling forward unconditional"
setting is required on the "voice service voip" section of the IOS configuration. This allows
forwarding of the Generic Type Descriptor (GTD) data of the call in the SIP INVITE to Unified
CVP in a multipart mime content type media format.

The Unified CVP SIP Service extracts the GTD section of the call and parses out the parameters
that are configured to be passed to Unified ICME in the payload field of the ICM Service's
"NEW CALL" message "usertouserinfo." ISDN call parameters, which are forwarded in the
GTD payload, as set in the Unified ICME script, cannot be sent in outbound SIP calls. In addition
to sending ISDN data inbound to Unified ICME, the GTD section of the inbound call leg will
be passed along untouched in the outbound call leg by the Unified CVP SIP Service.

Configuration and Administration Guide for Cisco Unified Customer Voice Portal Release 8.0(1)