Nortel 1000 Integration Manual page 26

Chapter 3 Deployment Planning
Considerations for Integrating the Application Gateway into an IP Phone Enterprise
Application Gateway Operation with a Router
Note
20
Application Gateway Network Integration Guide
When the Application Gateway straddles a firewall or is in front of a
router, it will need routes for reaching any subnets that are not
automatically available through your Default Gateway. You can configure
the Application Gateway so that it uses your routing tables or the routes
that you specify.
The following illustration shows an Application Gateway connected to a
application servers through a router in an IP phone enterprise.
The application servers in the illustration represent the variety of devices
that the Application Gateway will connect to, including application and
Web servers, LDAP servers, and call servers.
When an IP phone requests application content, the Application Gateway
accepts the request from the device and requests the content from the
back-end servers.