HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual page 141

3. If the call fails to connect, the Secure Router OS checks the backup dial
list in the primary interface for a second number, which references a
different backup PPP interface. If there is a second number, the Secure
Router OS attempts to connect to it.
Dialing In. When the Secure Router OS receives an inbound call, it follows
these steps (see Figure 3-15):
1. It uses caller ID to compare the call's number with the backup dial list
number configured for the PPP interface. (See Figure 3-17.)
2. If the numbers match, the Secure Router OS connects the call. The
primary link may already be down. However, you can also configure an
interface to answer backup calls even when its own primary connection
is up. In this case, the Secure Router OS closes the primary connection
and connects the backup call.
3. If the inbound call does not match a number in the backup dial list number,
the Secure Router OS terminates the call.
ProCurve# show running-config
!
!
int ppp 1
backup call-mode answer
backup number 5551111 digital-64k 1 1 ppp 2
Router only answers
calls with this
caller ID.
Figure 3-17. Backup Settings for Dialing In
The primary connection's logical interface can allow its backup interface to
originate calls, answer them, or both. At least one side of the connection must
be able to originate calls, and at least one side must be able to answer them.
Refer to Table 3-9 for all available backup call modes and the commands to
configure them.
Configuring Backup WAN Connections
Configuring a Persistent Backup Connection
Router answers
backup calls only
when PPP 1 is
down.
Router uses PPP 2 to
establish the
connection.
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