Cisco Cisco Customer Voice Portal 8.0(1)

Note: It is possible IOS will timeout before INVITE number from Unified CVP (to Unified
CM, gateway, etc.) As a practical setup, set the gateway sip-ua expires timer to higher than the
highest setting on the Unified CVP configuration. The minimum ring timeout is 60 seconds on
the IOS side. Unified CVP can set a minimum ring timeout on its outbound calls as low as
necessary.

Critical Error Message Playback on Abnormal Disconnects with SIP

The critical error message's playback works differently for SIP calls than it does for H.323 calls
because the Call Server will not perform media termination by itself, as the H.323 Service does.
Therefore, the SIP Service in the Call Server uses the SIP REFER method to refer the calls to
the IOS gateway "cvp-error" TCL scripted service for message playback. The purpose of this
is to define the ERROR DN (default 92929292) on the SIP Service of the Call Server in the
Operations Console.

Note: Critical Error messages will not be played if REFER blind transfers fail since the Unified
CVP SIP Service is not longer holding onto the call; it cannot take the call back and refer to the
error DN. (This also includes 302 redirect responses.)

How It 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 (see 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 the incoming call as using survivability or not; 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 needs to 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.

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

Configuration and Administration Guide for Cisco Unified Customer Voice Portal Release 4.1(1)