HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual page 171

Viewing Backup Configurations and Troubleshooting Backup Connections
In a PPP connection, when one end loses the connection the other does
as well. If both endpoints are allowed to place a backup call, the calls may
collide. In this situation, you may want to configure one router to answer
calls and one to receive them. (See "Setting the Backup Call Mode" on
page 3-59.)
You can also randomize backup timers to minimize the chance that the
local backup call will collide with a call from the peer router. (See "Setting
Backup Timers" on page 3-66.)
Finally, the router could be calling the wrong number. See step 2 for
troubleshooting this problem.
2. If you simply receive a "Connect failed" message, the router may not be
calling a valid number. Enter show backup int and view the backup dial
list for the connection. (See "Viewing Backup Settings" on page 3-85.)
Verify that the number is the remote site's correct number. You configure
the local site's number in the BRI interface configuration mode. If the
backup dial list includes the local number, the router will receive a "BUSY"
message.
Sometimes the Secure Router OS may delete a stored backup number—
for example, if you change a Frame Relay interface's DLCI. If necessary,
reenter the number.
3. If the number is correct, but the call still will not connect, increase the
connect-timeout interval. This timer determines how long the router will
wait for a call to connect before terminating the attempt. It should be at
least 60 seconds. (See "Setting Backup Timers" on page 3-66.)
The Router Will Not Answer the Peer's Call. You may receive a debug
message telling you that the router is ignoring a call because no match was
found for the call. Follow these steps:
1. Enter show backup int and view the backup dial list for the connection.
(See "Viewing Backup Settings" on page 3-85.)
2. Verify that the number is the peer's correct number. If necessary, remove
a faulty number and add the correct one.
When the router will not answer a call and does not receive any debug
messages, its own primary connection may still be up. For example, in a Frame
Relay network, one site's connection may go down, while the other's connec-
tion to its Frame Relay provider is still good. Check the primary interface (or
Frame Relay subinterface). If it is up, try changing its backup call mode to
answer-always or originate-answer-always. This will allow the local router
to establish the backup connection with the remote router.
Configuring Backup WAN Connections
3-91