Cisco Cisco Customer Voice Portal 8.0(1) Design Guide

The other chapters of this document treat the Unified CVP Call Server as a single component because 
those chapters have no need to examine it in any more depth than that. When discussing Unified CVP 
high availability however, it is important to understand that there are actually several parts to this 
component:

H.323 Service — Responsible for H.323 processing of incoming and outgoing calls as well as 
registering with the gatekeeper. The H.323 Service was known as the Unified CVP Voice Browser 
in previous versions of Unified CVP.

SIP Service — Responsible for processing incoming and outgoing calls via SIP.

ICM Service — Responsible for the interface to ICM. The ICM Service communicates with the 
VRU PG using GED-125 to provide ICM with IVR control. The ICM Service was part of the 
Application Server in previous releases of Unified CVP, but now it is a separate component.

IVR Service — Responsible for the conversion of Unified CVP Microapplications to VoiceXML 
pages, and vice versa. The IVR Service was known as the Application Server in previous Unified 
CVP versions.

 shows a high-level layout for a fault-tolerant Unified CVP system. Each component in the 

Unified CVP site is duplicated for redundancy. The quantity of each of these components varies based 
on the expected busy hour call attempts (BHCA) for a particular deployment. The following sections 
describe the failover strategy for each of these components.

191323

SIP Proxy /

Gatekeeper

SIP Proxy /

Gatekeeper

VRU PG

VXML

server

Call

server

CSS /
ACE  

VRU PG

VXML

server

Call

server

CSS /
ACE