System information

Troubleshooting ISDN Connections 17-379
ISDN: Router Does Not Dial
No dialer group
configured
Step 1 Use the show running-config privileged exec command to view the router
configuration. Check whether there are dialer-group interface configuration
command entries present for the interface.
Step 2 If the local interface does not belong to a dialer group, configure
the interface as part of a dialer group by using the dialer-group group-number
interface configuration command. This command associates an interface with a
dialer group.
Step 3 Make sure the group-number is the same number used in the associated dialer-list
global configuration commands.
Missing or
misconfigured dialer
lists
Step 1 Use the show running-config privileged exec command to view the router
configuration. Check whether there are dialer-list interface command entries
present for the interface.
Step 2 If there are no dialer lists configured, enter the dialer-list protocol or the dialer-list
list global configuration command to associate a dialer group with an access list.
In the following example, dialer group 1 is associated with access list 101:
dialer-list 1 list 101
Step 3
Make sure that dialer-list commands reference existing dialer groups and existing
access lists, or create the appropriate dialer groups or access lists before attempting
to dial.
Missing or
misconfigured access
lists
Step 1 Use the show running-config privileged exec command to view the router
configuration. Check whether the access list numbers specified in dialer-list
commands refer to existing access-list command entries.
Step 2 If the referenced access list is not defined, dialing does not occur. Configure access
lists that define interesting traffic and make sure the lists are referenced correctly by
dialer-list commands.
In the following example, IGRP
1
routing updates are classified as uninteresting
(they do not cause the router to dial), whereas all other IP packets are classified as
interesting:
access-list 101 deny igrp 0.0.0.0 255.255.255.255
255.255.255.255 0.0.0.0
access-list 101 permit ip 0.0.0.0 255.255.255.255 0.0.0.0
255.255.255.255
Step 3
If access lists are already present and they are referenced correctly by dialer-list
commands, make sure that the traffic you want to trigger the dialer is defined as
interesting by the access list.
Missing pri-group
command
On Cisco 7000 series routers, use the pri-group controller configuration command to specify
ISDN PRI
2
on a channelized T1 card.
Step 1 Use the show running-config privileged exec command to view the router
configuration. Check whether there is a pri-group command entry.
Step 2 If the command is not present, configure the controller with the pri-group
command.
Following is an example of a configuration for a Cisco 7000 series router with a
channelized T1 card:
controller t1 0
framing esf
line code b8zs
pri-group timeslots 1-24
1 IGRP = Interior Gateway Routing Protocol
2 PRI = Primary Rate Interface
Possible Problem Solution