Specifications
Chapter 7 Configuring Frame Relay
ISDN as the Backup WAN Connection
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Cisco 1700 Series Router Software Configuration Guide
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Verifying Your Configuration
To verify your router configuration to this point, confirm that the ISDN connects
dynamically to the remote site when the Frame Relay connection is disconnected.
Follow these steps:
Step 1 Remove the cable that connects the router to the Frame Relay services, or
otherwise force the DLCI(s) to become inactive. This action brings the line
protocol down.
Step 2 When the router generates routing updates, the ISDN line should begin dialing. If
the ISDN line does not dial, use the ping command as described in the
“Configuring the ISDN Interface” section.
Step 3 Reconnect the cable that connects the router to the Frame Relay services, or force
the DLCI(s) to become active. The ISDN line should disconnect dynamically.
Troubleshooting Problems with ISDN as Frame Relay Backup
Line
If you are having problems, follow some or all of these steps:
Step 1 Confirm that you used the broadcast keyword in the dialer map command. This
keyword causes dialing to occur with a flash routing update. If you do not use the
broadcast keyword, routing updates do not trigger dialing on the ISDN line.
Step 2 If you want to use the ISDN line even when the Frame Relay line is connected,
use dialer profiles. Otherwise, the ISDN line operates in backup mode only.
Step 3 If you are having problems, you can use some or all of the following debug
commands:
• debug dialer events
• debug isdn events
• debug isdn q931
• debug isdn q921
• debug ppp negotiation