How to setup internet redundancy 2

[grunt68]

Hello all:
I am trying to setup internet redundancy using a secondary 3G router for back up. My primary router is a Cisco 2811, the 3G router for back up does not have VRRP/HSRP capabilities. I understand I can put a "floating static" route on the Cisco and track my primary WAN so that if it goes down, it will route traffic to my 3G router.
Could I get someone to expand on this? Or if there is a different solution.

Thanks.

 

[burtsbees]

A floating static route is like
ip route 0.0.0.0 0.0.0.0 fa0/0
ip route 0.0.0.0 0.0.0.0 fa0/1 20
fa0/0 would be the primary, fa0/1 the secondary. The metric is higher on the secondary, which is why traffic will prefer the primary...until it fails---the secondary would be the next in line.

Burt

 

[wingatesl]

this technique relies on a hard failure of the connection to force traffic to the other interface. I have a blog post on how to have the router ping a host and if it fails change the routing table. It is called SLA tracking, only a few commands

http://www.inacom-sby.net/Shawn/post/2007/11/Cisco-IP-SLA-for-failover.aspx

Shawn

 

[jeter]

Very Cool I will have to lab this out!!


SPC NVARNG
Tek-TIP Member 19,650

 

[wingatesl]

Leave me a message if you need any help.

 

[unclerico]

I set this up in my lab last night and it worked flawlessly. My topology was set up like this: 3640 connected to a 2620XM and a 2610XM via serial cable and the 2620XM connected to the 2610XM via T1 x-over. I created a loopback interface on my "primary" ISP connection (2620XM) and had the sla monitor this interface with a ping every 10 seconds (i probably could have just used the physical serial connection, but I didn't). I did a continuous ping from a pc, shut down the serial connection on the "primary" and watched as i had only a few dropped packets while the default route changed to my "secondary". EIGRP noted the toplogy change and updated my routing table with the feasible successor routes without issue. Thanks for posting about the sla commands, I can definitely use them in my production environment.

oh, and sorry OP for hijacking your thread :-(

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