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Implementing Basic DDR 143
Step 2: Specifying Interesting Traffic
The entire configuration of DDR depends on how the traffic types that cause a call setup to
occur are triggered. This traffic is known as interesting traffic.
Cisco's implementation of DDR allows for as much or as little specificity of interesting traffic
as is deemed necessary; interesting traffic is defined by the creation of dialer-lists that can
specify that an entire protocol suite, no matter the level of traffic, can trigger a call setup.
Dialer-lists can be associated with standard or extended access lists to be specific to various
traffic types. Rather than associating an access list with an interface, it is associated with a
dialer-list (discussed in the "Specifying Interesting Traffic with Access Lists" section in this
chapter).
Example 6-4 shows a basic configuration in which all IP traffic has been specified as interesting.
This is specified in the dialer-list line. The dialer-list is associated with the proper interface
using a dialer-group line, as shown.
Note that the list number and the group numbers are identical. This number ties the dialer-list
and dialer-group together. This number cannot be re-used by any other dialer-list or dialer-
group in the same router.
The remote router configuration should be similar. Example 6-5 details the basic configuration
of the remote router.
Example 6-4
Basic DDR Configuration on RouterA
RouterA(config)#isdn switch-type basic-5ess
!
RouterA(config)#interface BRI0
RouterA(config-if)#ip address 10.12.1.1 255.255.255.0
RouterA(config-if)#encapsulation ppp
RouterA(config-if)#dialer idle-timeout 180
RouterA(config-if)#dialer map ip 10.12.1.2 5552222
RouterA(config-if)#dialer-group 1
!
RouterA(config)#dialer-list 1 protocol ip permit
Example 6-5
Basic DDR Configuration on RouterB
RouterA(config)#isdn switch-type basic-5ess
!
RouterA(config)#interface BRI0
RouterA(config-if)#ip address 10.12.1.2 255.255.255.0
RouterA(config-if)#encapsulation ppp
RouterA(config-if)#dialer idle-timeout 180
RouterA(config-if)#dialer map ip 10.12.1.1 5551111
RouterA(config-if)#dialer-group 1
!
RouterA(config)#dialer-list 1 protocol ip permit