Dial-on-Demand Routing (DDR)
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804A(config)#access-list 110 permit tcp any any eq telnet
804A(config)#int bri0
804A(config-if)#dialer-group 1
In the preceding example, you configure the dialer-list command
to look at an access list. This doesn't have to be IP; it can be used with any
protocol. Create your list, then apply it to the BRI interface with the dialer-
group
command.
Verifying the ISDN Operation
The following commands can be used to verify legacy DDR and ISDN:
Command
Description
ping
and telnet
Great IP tools for any network. However, your interesting
traffic must dictate that Ping and Telnet are acceptable as
interesting traffic to bring up a link. Once a link is up, you
can ping or telnet to your remote router regardless of your
interesting traffic lists.
show dialer
Gives good information about your dialer diagnostic
information and shows the number of times the dialer
string has been reached, the idle-timeout values of each
B channel, the length of the call, and the name of the router
to which the interface is connected.
show isdn active
Shows the number called and whether a call is in progress.
show isdn status
A good command to use before trying to dial. Shows if
your SPIDs are valid and if you are connected and
communicating with layers 1 through 3 information to the
provider's switch.
sho ip route
Shows all routes the router knows about.
debug isdn q921
Used to see layer-2 information only.
debug isdn q931
Used to see layer-3 information, including call setup and
teardown.
debug dialer
Gives you call-setup and teardown activity.
isdn disconnect
int bri0
Clears the interface and drops the connection. Performing
a shutdown on the interface can give you the same results.
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