I've read through a lot of messages and have a decent idea of what needs to happen here, but I'd love to hear from some folks with the same scenerio as mine and see what they have to say. Although I've done a lot with cisco and vpn I am not as familiar with multiple-wan links and redundancy.
What we have is a point-to-point T1 between two locations each on their own private subnets. We are looking to add a backup line at each location, something like cablemodem or DSL, static IP, no pppoe or anything like that.
I would like to use the T1 as a primary line and do an automatic failover to the cablemodem, using a site-to-site VPN.
First off, can I do all of this with just one device on each side? This would be ideal as we already have 1800 series routers at each end, we will just add ethernet interfaces as necessary.
I'd assume I would leave the serial and LAN connections alone and create new Tunnel interfaces on each end to do an IPSEC VPN between them. I'm not sure if EIGRP, BGP, or OSPF would be ideal here. I'm also not sure how the router would know when to send traffic over the VPN or when to send it over the serial.
Would it be better just to use floating static routes on both ends?
I'm just a bit confused, any tips or sample configs would be great.