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Community Member

Dial backup for FR link

I have 3662 central router and 150 branched on FR links HUB and spoke config.

branche routers will only have default route to the HO router.


I need PSTN dial ackup for the FR link.

Also, I need the dial backup link to be kept activated irrespective of the interesting traffic. I need the backup linkto stay up untill primary FR link comes back.

I am trying with dialer-watch to watch the default route. I also defined a static default route with higher ad. distance to router traffice in the dial-back scenario.

This method has two problems.

1. Once the primary ois down, backup link is activated, but after short duration, the line is reset and re-dials.

2. If the primary link is down when the router powered- on. Then the routing table has static default route, hence router wil never dials to initiate the connection.

What is the best method to achieve the requirements ?

Cisco Employee

Re: Dial backup for FR link

The dialer-watch method should work fine with your requirements. We need to know what the PSTN links (analog or isdn) went down and re-dials. "debug dialer" will show us the reason for that.

Dialer-watch should not keep the pstn link up regardless of inetresting traffic and even if the idle-timeout expires. It will only bring down the backup link is the watched route learned via primary link.

visit following link for more

Now, 2nd point, the backup link should be activated regardless of default route as dialer-watch works on watched routes. So we need to debug that issue.

Here is the link which compares all the backup methods

Community Member

Re: Dial backup for FR link

For the second point, what I Learned is , when I define the router to be watched is the defalut route ( ) and do not want to run routing prorocol over the backup link I have the following defalut rotute defind;

ip route 150

When the router powers up, if the promary link is down, when I query teh route table I can see the floating static defalut route has been installed irrespective of the backup link UP/DOWN as follows; is variably subnetted, 3 subnets, 2 masks

C is directly connected, FastEthernet0

C is directly connected, Loopback1

C is directly connected, Async5

S* [150/0] via

Therefore , I bilieve that the router "thinks" that the route to be watched, now via the static route , as the PRIMARY link.

Since dialer watch assumes that the "PRIMARY" link is UP, it is never going to dial.

Any thoughts ?

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