Cisco Cisco Customer Voice Portal Downloads

 shows an H.323 network with three Gateways (Huey, Dewey, and Louie), three ISN nodes, 

and a Domain Name Server (DNS). Each ISN node contains two Voice Browsers with the IP addresses 
noted.

Suppose this network processes calls made to several toll free numbers (800-555-0020 through 0029) 
and that each call requires ISN treatment before it can be routed to its final destination. In addition, to 
enhance performance, Gateways should first route ISN calls to Voice Browsers in the nearest ISN node 
(For failover purposes, if the nearest ISN node is unavailable, the Gateways should route ISN calls to 
Voice Browsers in an alternate ISN node.)

Two ways to accomplish this would be to configure dial-peer Session Targets:

As IP Addresses (for example, 10.10.10.11)

As Domain Names (for example, isn_Node2@cisco.com)

By default, all dialed numbers not defined as dial-peers are routed to the PSTN.

Preferences can be assigned to Session Targets—whether specified as IP Address or Domain Names—so 
you can indicate a hierarchy of which Voice Browser should be routed to first, which should be second, 
etc. 

 illustrates a possible preference configuration for Gateway Huey:

ISN_Node1

10.10.10.11

0

10.10.10.12

0

ISN_Node2

10.10.10.21

1

ISN_Node3

10.10.10.31

2