IPSEC VPN as Serial/WAN Backup ?

[nickbettison]

Hi,

We have a traditional WAN running OSPF, has anyone tried backing up their links over the Internet.

So, Remote site; something like a 2800 with a Serial & ADSL WIC. The Point-Point link goes to "datacenter a" and the VPN goes to an ASA at "datacneter b".

Does anyone know of any examples ? As one end is a router, would I still need GRE tunnels ? (Examples of OSPF over IPSEC without GRE, have pix/asa's on both ends)

Thanks in Advance,

Nick

[hacronin]

I know of a few companies doing just such a thing to save $$. You will need to run GRE through the IPSEC tunnels to support routing protocols and any other multicast traffic you may have a need to transmit, even though one end is a router. IPSEC operates at layer 3. This adds quite a bit of overhead to the packet so make sure your OSPF metrics are set such that the WAN link is preferred over the Internet link.