Flex Links Backup Interface


For this lab you need REAL hardware. You can’t use switches in GNS3!

You need at least Catalyst 2950 switches for this lab.

The network agency corporation has hired you as a spanning tree specialist. One of their customers has issues with a switched network that only has fiber connections. Every now and then there’s a problem with the fiber and as a result layer 2 loops occur. It will take two months for the fiber company to check all cables/connectors so you want a temporary solution…


  • Configure SW3 so the fa0/14 interface is the active interface. fa0/16 should be the backup interface.
  • Whenever interface fa0/14 on SW3 fails the fa0/16 interface should take over.

It took me 1000s of hours reading books and doing labs, making mistakes over and over again until I mastered all the switch protocols for CCNP.

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Basic IOS for the switches should be sufficient. No special features needed.



Flex Links

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 Video Solution:

Configuration Files

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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 GNS3Vault.com where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on http://networklessons.com

1 Comment

  1. Do 2950’s support this feature? I could only configure “switchport backup interface f0/16” on my 3550 and 3560’s.

    The topology of SW1 and SW3 deviates slightly from your other labs. Typically, it has been connected SW1 Fa0/17 to SW3 Fa0/13.

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