3640 router and internet redundancy

Unanswered Question
Apr 24th, 2007

We have currently one broadband internet connection from our service provider and we would be soon having another internet link from another provider.

What configuration is required to terminate both the INTERNET links on cisco 3640 router.

Our Company requirement is if one internet link fails automatically the load is transfered to another link.

The Internet links are currently used for INTERNET Browsing only???

Router at my end has 3 Fast Ethernet Ports.

Currently on the router the configuration is as follows

interaface f0/0

IP address of my LAN

Interface f0/1

IP address of Internet service provider

ip route

I need help on how to terminate the two internet link on the router and make it work as failover intially and later load-balancing.

Please provide a sample configuration

I have this problem too.
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desai.jaideep Tue, 04/24/2007 - 01:40


As far as redundancy is required, this can be easily done using floating static routes:

Say, you have two ISPs, their static route config is as follows:

ip route

ip route 50

So if the gateway (ISP1) is down, the second ISP2 is taken over.

As far as load-sharing is concerned, you need to have BGP routing enabled from your ISPs and need to configure BGP on ur routers.

For that you will require ASNs.

Hope that will help.



spremkumar Tue, 04/24/2007 - 20:30


If your links are connected onto an ethernet port of a router and if you require redundancy with primary/secondary scenario you need to have a special feature called object tracking which will help you out to sense/detect the link failure which is connected onto an ethernet port.

Normally with the link connected onto the ethernet port the port may not go down untill unless theres physical disconnect on the cable or if you remove the cable out of the ethernet port.

When theres any probs with the media which connects you to the SP the ethernet port may not go down and will still remain up making you traffic to be dropped.

So in this case you need to have a tracking mechanism which you keep on sending icmp pings (similar to keepalive packets) and probe the remote destination.

When it looses the reply for the icmp packets send it assumes the link is down and remove starts forwarding the traffic via the secondary link provided you have a secondary link and have your routing configured accordingly..




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