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New Member

Automatic Back-up link.

Hello!

I am using a 3662 cisco router with async and BRI modules. I have this kind of config.

S1/0

back-up interface async or BRI X

back-up delay X X

I have a line connected to my back-up link, ISDN and Analog line (working).

Whenever the main link comes down, the back-up doesn't come-up automatically considering that there is a traffic flowing intended on the other destination. The back-up only work if and only if I will ping the other end, it will start to dial until it complete the proper authentication and the connection established.

I have a proper static route with a valid administrative distance. I use a loopback interface and make use of it for the IP address assignment of my Async/Bri port.

Could anybody here share their idea on can I properly configure my back-up link.

Thanks and Best Regards,

dennis

5 REPLIES
New Member

Re: Automatic Back-up link.

Hi,

Turn debug dialer to check why the back up do not kick in.Do you have a floating static route to reroute the packet when the main link is down?

cheers!

New Member

Re: Automatic Back-up link.

Thanks, I'll try to run debug and see why is it not kick in.

Yeah I have a floating static route.

regards,

dennis

New Member

Re: Automatic Back-up link.

Is the backup interface in standby mode ?

cheers!

csyeo

New Member

Re: Automatic Back-up link.

HI

Make sure that u r not using this command on both the sides, also assign the IP address to the dial interface n then try again (if u r saying that ur routes r properly configured n the dial up line is okay then it must work)

New Member

Re: Automatic Back-up link.

This may sound daft, but I presume you have defined interesting traffic with dialer-group X under the BRI or Dialer int?

Is your static route pointing to a destination address or the BRI?

Try having one static route to the destination next hop(Admin Dist 1) and one pointing to the BRI (AD 0) and put in an admin distance higher than the one you have already.

You could run OSPF between them, reduce the timers to bring up your ISDN faster, apply outbound ACL's to interfaces that go out to the rest of your network to prevent OSPF broadcasting all over the place!! REMEMBER to make your Dialer interfaces PASSIVE under the OSPF process or you'll run up a MONSTER ISDN bill!!

Of course this depends if you are running time-critical apps as OSPF will take 50 secs to converge using the default timers.

Hope this is of some help.

Ali

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