Using Primary & backup Internet Connection Real Time

Hi!
I have two internet connections, primary Radio Link while secondary Satellite connection. Both of the links from the same ISP and have same Real IP. Whenever the primary link goes down one have to manually turn on the backup connection and sometimes this downtime really impact the online application we are running.

Now the scenario is like this Internet connection is terminating from there Indoor unit / Modem into my Cisco 800 series router. There is a VPN connection established through that router on that particular real IP.

So the reason of having same IP on both Internet connection is simply enabling the backup link once the primary goes down and without making any change in the configuration at my end as well as site (where the VPN concentrator is risiding).

Now there is a limitation that i can have only 1 VPN connection from the reomote site.

=> How can i achieve real time backup connection (without manually changing the connection)? I have read about Tracking option in router but will it work in my case as i can have only 1 VPN connection!


I have seen this thing implemented in another scenario, where primary connection was terminating in E1 port of router and backup in FastEthernet ports with Internal network, using VLAN to isolate the internal traffic with that backup conection.

Both connections use the same IP so that would make it difficult if not impossible. If they used different IPs they could both be 'online' and by making use of metrics in your routing table it would use one connection. When that goes down it'll take the other route. It would still mean your VPN will go down momentarily but it should restore (basically redial) and use the other connection.

But having different IP's mean i should have two VPN different VPN connection, which is not possible!

No you still would have 1 VPN connection at any one time.

Obviosuly yes but the restriction is I can have one VPN connection only! With two IP's i have to register two VPN connections right ?

Just a thought came in mind!
What if I introduced a Switch and terminate both connections in it, when one goes down other gets UP automatically just like Spanning Tree Protocol. Is it possible ?

No, both links use the same IP address, you'll get an IP conflict.

It's more or less like this:

Code:

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[vpn box]-------------[router1]------>link1
              \------[router2]------>link2

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The outside addresses of the routers are different or you won't be able to get the links online (ip conflict at the ISPs end). The VPN would choose which router based on the routing metric.

The link is in between VPN box and the Router!!!!

Remote Site
VPN BOX---------------ISP Link --------- My Router

Quote:

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I have two internet connections, primary Radio Link while secondary Satellite connection.

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Means you have 2 ISP links.

If you see further i have mentioned : -

Both of the links from the same ISP and have same Real IP.

So one ISP two different types of connection one surving as primary (Radio Link) other as backup (satellite).

And my reply was:

Quote:

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Both connections use the same IP so that would make it difficult if not impossible. If they used different IPs they could both be 'online' and by making use of metrics in your routing table it would use one connection.

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Even if its difficult i must go for it!!!!!! If not what other alternatives I can have ?

While coming to office today i came across one more idea!
See attacment

Now the thing is i will Disable the port of Backup link and once the primary link goes down i will enable the backup link port. The Real IP is configured on my router WAN interface and static route is defined to gateway / indoor unit IP which is also same for both the connections.

If i wont deploy this than i have to move the router in the deployment area which is 300 m away from the server Room, so when the link will go down one must be going all the way there and plug in the backup link cable.