Mon May 29, 2023 5:17 pm
It depends on your objectives. It also depends on factors such as throughput to the ISP's, whether you're currently running BGP with them, if you're NATting anywhere, etc.
OSPF alone, when configured correctly, will ensure each router's path to the next one will take the shortest path, and if one (or more fails), it will take the preferred backup path, depending on the costs you set.
But there's more than just OSPF to help with this. You can also use BGP, especially in a multi-homed setup like you have. Also, when configured correctly, this can ensure each router sends the traffic back out over the ISP closest to the remote end, or over the largest pipe first, unless it's down.
BGP + OSPF (with a pair of route reflectors) would be a clean, straightforward way to go with this particular setup.
All of these CRS317's can route in hardware (L3HW offload), presuming you're not doing any kind of NAT or firewall on the 317's directly. That means they can all handle BGP + OSPF and pass traffic at wirespeed.