ISDN BRI & DDR

[frenzeus1881]

I am currently preparing for the BCRAN exam. I’m not too clear with the sequence of process for the ISDN BRI connection to remote end using DDR.

From the viewpoint of the router, there is incoming traffic into the router.
1. The dialer-list would check if the traffic is interesting or not.
2. If it is interesting traffic, it then assigns the traffic to an interface to connect to the remote router via the interface that has been configured with dialer-group matching dialer-list dialer-group-number.
3. Say the interesting traffic is to go out of interface Bri0, where a dialer-map exists which maps it to the next-hop-address and number to dial to connect to the remote router.

Since the interesting traffic/packets already know how to reach the other end of the router to establish the connection, where does static route come into place in the list of sequential steps?

Can anyone help me out here? I would really appreciate!

 

[lgarner]

As I understand it, the static route should be inserted as step 1. Cisco says that the route "creates the Demand", in DDR.

The route specifies where traffic is to go. The dialer-list specifies what's "interesting". You very likely would not want the ISDN link brought up for just anything, like pings, routing updates, etc.

So,
First, does the traffic go out via the BRI?
Second, should the traffic type cause the link to come up?

This looks like a good summary:

http://www.cisco.com/en/US/tech/tk801/tk379/technologies_configuration_example09186a0080094abd.shtml

 

[frenzeus1881]

alritee man... thanks lots!! u're a great help!