So I have a couple of questions and was curious about what the community here thought about this theory. We are colo'ing a rack for redundancy offsite and have a single layer 2 connection between that and our main location (dedicated fiber). We have an ISP at the colo facility and a different ISP at our main location. We're planning to announce our public /24 via BGP and a public AS to both providers to provide redundancy for our /24 both incoming and outgoing.
I've attached a basic picture of this environment for what we want to do. For the moment ignore the single point of failure between the switches/ISP/locations, those will be redundant soon.
My questions are these:
1) For redundancy between the firewalls and the routers, is Layer 2 or Layer 3 recommended?
2) If we go Layer 3, I assume we would need to use public IP's on those links and not private reserved IP's? (Wouldn't the private IP's show up like in a traceroute/etc?)
3)I've red a lot about spanning tree, hsrp, vrrp, osp redistribution, etc. I'm having a hard time figuring out exactly what tech/protocols to use for making the area between the routers and the firewalls redundant.