HP 7102dl - ProCurve Secure Router Configuration Manual page 109

example, you assign the demand interface an IP address. From this interface,
you apply the ACL that defines the interesting traffic that triggers the dial-up
WAN connection.
The demand interface is different from other logical interfaces, however. For
one thing, the demand interface is not bound to a specific physical interface
or interfaces. Instead, the demand interface is associated with the pool of dial-
up interfaces used for backup.
The demand interface must also handle its status differently: it must always
be up, whether or not the physical dial-up interface associated with the
demand interface is up. Because the demand interface cannot actually be up
if the Physical Layer is down, it "spoofs" an up state. As a result, the demand
interface can be listed as a directly connected interface in the router's routing
table, even when the dial-up interface is not in use.
Because the demand interface spoofs an up state, you can also create routes
to any of the networks connected through a dial-up interface. When the
ProCurve Secure Router detects traffic that must be routed through a demand
interface, it processes the extended ACL that has been applied to it to select
interesting traffic. If the traffic matches that ACL, the router attempts to
establish the dial-up connection.
After the physical connection is established, the ProCurve Secure Router uses
PPP as the Data Link Layer for the dial-up connection. To ensure that backup
connections are only established with authorized routers, you should config-
ure PPP authentication for the dial-up connection.
To configure the demand interface, complete the following steps:
1. Create a demand interface.
2. Configure an IP address for the demand interface.
3. Apply the ACL that defines the interesting traffic to the demand interface.
4. Specify whether the demand interface can originate a call, answer a call,
or both.
5. Create a resource pool.
6. Configure connect-sequence settings.
7. Configure timers, caller, and hold queue settings (optional).
8. Configure caller settings (optional).
You must complete steps 1-6. Steps 7-8 are optional.
Configuring Backup WAN Connections
Configuring Demand Routing for Backup Connections
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