In the Figure, interface serial 0 is the primary interface. From the configuration in the
Figure, you can tell that if the primary interface reaches a load threshold of 60 percent or higher, the backup interface (BRI 0) will be activated. The secondary line will deactivate after the primary line traffic load falls to within 5 percent of the primary lines bandwidth. The example in the Figure illustrates only the commands to enable a backup. The interface must also be configured as needed (for DDR, Frame Relay, X.25, and so on).
You
have just installed an ISDN line to be used as
standby reserve bandwidth your Frame Relay connection between the Atlanta and Orlando
office. Configure DDR on the BRI interface of
the Orlando router. Configure Frame Relay on
the serial interfaces connecting to the Frame Relay
network. Configure parallel static
routes so that when both links are up traffic
will load balance between the two links.
You
have just installed an ISDN line to be used as
standby reserve bandwidth for your Frame Relay
connection between the Atlanta and Orlando
office. Configure DDR using a dialer interface
on the Orlando router. Configure Frame Relay on the serial interfaces connecting to the
Frame Relay network. Configure this to work
successfully with IGRP. EIGRP could also be
used.