There is such, but the cost I saw while at Motorola was in the 25 thousand dollar range. It doesn't mean you can't look into Linux and implement it yourself. IP failover is the term for failure handling. Modem bonding is the term for bonding such things as well.
I will not supply you a ready to use solution since the ones I know of are for commercial use and in the 5 figure range. I do know that such can be done with Linux server boxes.
Let me share a few areas that will need attention. First, you must fix the DNS issue. Pretty easy to solve since your Linux box will now have the DNS (server) and you can use the DNS from each link to populate the local DNS cache. If an external DNS is unreachable, then the Linux DNS will timeout and try the next entry. This will work.
Web browsing will work just fine. But P2P and voice chats fail horribly since inbound packets lose the link.
Best of luck in your setup and configurations.
Bob
I have two broadband connection. I want to use both broadband simultanously so that when one off broadband will down OR overloaded, in such cases it will automatically switch over to second broadband. Please tell me is there any hardware or software for this ?
Thanks

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