Cisco IOS Cookbook, 2nd Edition

Using OSPF on Dial Interfaces

Problem

You want to use OSPF on a dial interface, but you don’t want the protocol traffic to keep the link active unnecessarily.

Solution

In this example, Router4 will dial into Router1 by using an ISDN circuit:

Router4#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router4(config)#username Router1 password 0 cisco
Router4(config)#interface BRI0
Router4(config-if)#ip address 192.168.15.4 255.255.255.0
Router4(config-if)#encapsulation ppp
Router4(config-if)#ip ospf demand-circuit
Router4(config-if)#dialer map ip 192.168.15.1 broadcast 4165550000
Router4(config-if)#dialer-group 1
Router4(config-if)#isdn switch-type basic-ni
Router4(config-if)#isdn spid1 416555001000 4165550010
Router4(config-if)#isdn spid2 416555001100 4165550011
Router4(config-if)#ppp authentication chap
Router4(config-if)#ppp multilink
Router4(config-if)#exit
Router4(config)#dialer-list 1 protocol ip permit
Router4(config)#router ospf 87
Router4(config-router)#network 192.168.15.0 0.0.0.255 area 10
Router4(config-router)#exit
Router4(config)#end
Router4#

The configuration of the other router is similar, although it does not require the ip ospf demand-circuit command:

Router1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#username Router4 password 0 cisco
Router1(config)#interface BRI0/0
Router1(config-if)#ip address 192.168.15.1 255.255.255.0
Router1(config-if)#encapsulation ppp
Router1(config-if)#dialer-group ...