Cisco Cisco Unified Customer Voice Portal 11.0(1)

Call Server: ICM Service

This software module is responsible for all communication between Unified CVP components
and Unified ICME. It sends and receives messages on behalf of the SIP Service, the IVR Service,
and the VoiceXML Service.

The ICM Service is a software module that always resides in the Call Server.

Call Server: SIP Service

This software module is a SIP Back-to-Back User Agent (B2BUA). On the front end, it supports
two SIP call legs, one incoming and one outgoing. This component does not terminate RTP
(Real-time Transport Protocol) traffic; it only deals with SIP messages. On the back end, it
works with the ICM Service to implement an interface to Unified ICME for call control functions
only (no VRU scripts).

The purpose of a B2BUA is to act as an active intermediary for a call, communicating with both
the source and destination legs of the call, and providing third-party call control capabilities on
behalf of a third-party device such as the Unified ICME CallRouter. Because it must track the
call throughout its life, it becomes a key source of call-level reporting data and a natural place
for moderating call switching resources.

Generically speaking, a SIP B2BUA is two User Agents (UAs). The device receives incoming
calls in one UA, and immediately creates an outgoing call via its other UA. Thereafter, all SIP
messages from either one are forwarded to the other. What makes Unified CVP’s B2BUA
particularly useful is the fact that it puts Unified ICME in between the two legs. On incoming
calls it asks Unified ICME where the outgoing call should be addressed. Once the call has been
delivered, Unified ICME has the opportunity to end the outgoing leg and reconnect it to a
subsequent destination. In practice, there will typically be a delivery to the VRU leg, a take-back
and delivery to an agent, and subsequent take-backs and deliveries to subsequent agents or back
to the VRU leg.

The SIP Service is a software module that always resides in the Call Server.

Call Server: IVR Service

This software module creates the VoiceXML pages which implement the Unified CVP
micro-applications based on Run Script instructions received from Unified ICME.

The IVR Service functions as the VRU leg (in Unified ICME parlance), and calls must be
transferred to it from the SIP Service in order to execute micro-applications. The VXML pages
created by this module are sent to the VXML Gateway to be executed.

There is a special micro-application that causes the IVR Service to generate a "wrapper" VXML
page. This VXML page instructs the VXML Gateway to invoke an application on the VoiceXML
Server.

In deployments which use H.323 instead of SIP, the IVR Service can act as the switch leg as
well. The deployment includes an H.323 Service, which interacts with the IVR Service for call

Planning Guide for Cisco Unified Customer Voice Portal 4.0(1)