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redundancy config

Hi All,

I have a question about making redundant links to a remote office. currently they have a 1701 adsl router with dsl connection, but we will be putting in a t1 soon. i was wondering if there was a way to let a switch know that a certain port, say the port coming from the t1 router, to always be on and the port coming from dsl router to always be off...UNLESS the link goes down on the T1 side. I know there are a lot of configurations for redundancy, i just thought since we have the dsl we could keep it and use it somehow. any suggestions?

thanks,

R
Reply to
rhltechie
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Hello,

if you want the xDSL interface to be only active when the T1 goes down, you could use the =B4backup interface=B4 command on the serial interface:

interface Serial0 backup interface Dialer1

and put two static routes in, where the one pointing to the dialer interface would have a higher administrative distance:

ip route 0.0.0.0 0.0.0.0 Serial0 ip route 0.0.0.0 0.0.0.0 Dialer1 250

Since you are paying for the DSL, you might as well consider introducing load-balancing. By enabling CEF globally and putting in two equal cost static routes, you router will do per-destination load-balancing:

ip cef ! ip route 0.0.0.0 0.0.0.0 Serial0 ip route 0.0.0.0 0.0.0.0 Dialer1

Is that what you are looking for ?

Regards,

snipped-for-privacy@solutionfinders.nl

Reply to
helpdesk

yes, thats exactly what i was looking for! thanks for your reply. i am not sure about the load balancing, we plan to do some qos configs and such, so i know dsl wont do that. and then we get into having to configure different routes for different traffic. not sure which route to really go there.

Reply to
rhltechie

Also checkout

Reliable Static Routing Backup Using Object Tracking:

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and

Dialer Watch:

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Reply to
Merv

And don't forget Vincent Jones's book "Reliable IP Networking Using Cisco", which has many examples of ways to implement network redundancy.

Reply to
Barry Margolin

Thanks for the endorsement, Barry. Just a correction on the Title, it's "High Availability Networking with Cisco" although the title you gave it is a good description.

Quick note to Merv (and anyone else looking for a copy of my book): It has been out of print for a while and the remainders appear to have all been snapped up (there is one used copy up on Amazon for $175!, so for now the best buy is over on B&N where there are still a few used copies at more reasonable prices), you can follow the links from my web site at

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If anyone wants an autographed copy, send me email. I still have a couple of personal copies I might be convinced to part with.

Good luck and happy designing!

Vince

Reply to
Vincent C Jones

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