HP 7102dl - ProCurve Secure Router Configuration Manual page 101

Edge Switch
Edge Switch
Edge Switch
Core Switch
192.168.1.0
192.168.2.0
Core Switch
Edge Switch
Edge Switch
Figure 3-3. Using Demand Routing for Backup Connections
Demand routing has another advantage: it supports two-port ISDN modules.
If you are not using all of the narrow slots in your ProCurve Secure Router,
you can purchase a two-port ISDN module and use it as a primary WAN
connection or as a backup to other primary WAN connections. To use the two-
port module for backup connections, you follow the instructions outlined in
Chapter 8: Configuring Demand Routing for Primary ISDN Modules in the
Basic Management and Configuration Guide, with one exception. Rather
than creating a static route to the far-end network, you create a floating static
route, ensuring that the administrative distance for this floating static route is
higher than the administrative distance for the route through the primary
interface. For more information about static routes, see "Configuring a Float-
ing Static Route for a Persistent Backup Connection" on page 3-69.
If you purchase this two-port ISDN module, you can use Multilink PPP
(MLPPP) to aggregate channels across ISDN lines, increasing bandwidth for
the dial-up connection.
Frame Relay
over E1
Backup ISDN
Main Router
connections
Frame Relay
over E1
Configuring Backup WAN Connections
Determining a Backup Method
Branch Office B
Switch
Branch Router
Switch
The backup ISDN connection to Branch Office B is
triggered only when the primary interface on the Main
Router goes down and traffic with destination address
192.168.3.0 /24 or 192.168.4.0 /24 is forwarded to demand
interface 1 on the Main Router.
Branch Office C
Switch
Branch Router
Switch
The backup ISDN connection to Branch Office C is
triggered only when the primary interface on the Main
Router goes down and traffic with destination address
192.168.5.0 /24 or 192.168.6.0 /24 is forwarded to demand
interface 2 on the Main Router.
192.168.3.0
192.168.4.0
192.168.5.0
192.168.6.0
3-13