Cisco Cisco Unified Customer Voice Portal 11.0(1)

This section describes CVP inbound call routing and the different ways in which inbound calls can be 
routed to the CVP using H.323 protocol.

At the highest level, CVP Inbound call routing on an H.323 IP network is determined by the presence or 
absence of an H.323 Gatekeeper.

The choice of whether to use a Gatekeeper is typically determined by the network’s size and/or 
complexity. In general:

Smaller/simpler networks consisting of 100 or less H.323 endpoints can function without using a 
Gatekeeper. 

Larger, more complex networks often require a Gatekeeper to consolidate routing information.

Throughout the 

 section, an CVP node is assumed to consist of one or more physical 

Voice Browser machines, which are controlled by a logical Application Server through VXML, and the 
Voice Browsers function as H.323 Gateways.

A Gateway (GW) is an H.323 or SIP device that allows a standard PSTN-based phone, using TDM 
technology, to access an IP-based network.

There are a variety of ways to tell the Gateway where to route to find the Voice Browser. For instance:

The NAM/ICM can be configured to tell the PSTN network to route the call to a VoIP Gateway.

The Gateway can be configured to directly route a call to the Voice Browser based on information 
provided from the public network or NAM/ICM.

The Gateway can query a Gatekeeper, which can provide centralized control for a number of 
Gateways.

A Gatekeeper (GK) is an H.323 device that controls route requests originating from H.323 endpoints.

Gatekeepers can provide additional services such as bandwidth control, and permit access to advanced 
routing servers such as Cisco’s NAM/ICM.

The Gatekeeper also has an interface to the NAM/ICM which is called Gatekeeper TMP, which allows 
the Gatekeeper to query a NAM/ICM system for specific customized routing instructions.