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ISDB backup dialing problem

Hi all,

I'm having a problem to initiate a backup ISDN dial-up (DDR) when my main link is down. Below shows the physical connections of my network.

Router(ISP)--Microwave Radio--Microwave Radio--Router

--------ISDN (BACKUP)---------------

My client router is connected to the ISP router via microwave link. The microwave radio act as a bridge transparantly. The connection between the radios and my client router is "10 base-t". When the microwave link(main link) is down, my client router will initiate a dial-up to the backup ISDN link.

My problem is, the router 10base-t interface will see the physical int. and protocol is up even though the microwave link is down (which is normal) but data will not go through and it won't initiate the dial-up!

Is there any way that I can configure the router to initiate the dial-up when it sense that data is not going through the main link?

The routing protocol that I'm using is OSPF, the router on the ISP is Cisco 7500 and on the clien side is Cisco 2620. Hope you guys can help. Thanks.

VIP Purple

Re: ISDB backup dialing problem


assuming that, since you use OSPF as your routing protocol, when the microwave link is down, there is no OSPF routing entry in the routing table, you could use the dialer watch feature.

Here is what the configuration would look like (assuming you are using DDR):

interface BRI0

--> Use a dialer map for the IP address/network which is the same network as being watched

dialer map ip x.x.x.x name RemoteRouter xxxx broadcast

dialer watch-group 1


dialer watch-list 1 ip x.x.x.x

Just make sure that the network in the dialer map statement and the network in the dialer watch list match, and that these networks appear exactly like that in the routing table.

For more info on Dialer Watch, check out the following link:



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