Backup Interface


You are responsible for a number of routers of a network that connects multiple cities. Whenever router Barcelona sends traffic towards Boston it has to use the link to Tilburg. Unfortunately it is load balancing since the paths are equal. You don’t want to make any changes to the routing protocol because you don’t want to impact the whole network. You decide to configure a backup interface on router Bar


  • All IPv4 addresses have been preconfigured for you.
  • EIGRP has been configured for connectivity.
  • Configure router Barcelona so F1/0 is a backup interface. Whenever F0/0 goes down it should enable F1/0.




Backup Interface

Video Solution:

Configuration Files

You need to register to download the GNS3 topology file. (Registration is free!)

Once you are logged in you will find the configuration files right here.

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Written by René Molenaar - CCIE #41726

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About the Author: Rene Molenaar

René - CCIE #41726 is the creator of where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on


  1. I ‘ve downloaded ZIP file and when I opened topology with GNS, I got message couldn’t connect to server and topology didn’t open. M’i missing anything or is there any alternative would you like to suggest?

  2. what if interface f0/0 on tilburg goes down then our serial link will stays up and it will not be able to any eigrp route, moreover our backup link is also stays down as well


    1. True this only works locally for the router, it doesn’t care about any other interfaces in the topology. We can solve this however by using object tracking and IP SLA. Take a look at some IP SLA labs and object tracking to learn how 🙂

  3. Hi Rene

    I try it on Static route and not working, so I try again using Eigrp still not working.
    I use FastEth on both interface in Router Barcelona, if this only working if I use Serial link and FastEth and also dynamic routing??


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