https://wp.scsiraidguru.com/?page_id=2334
I created this GRE tunnel using the loopbacks on iosv-1 and iosv-2 as the source and destination. I created static routes for the endpoints on each router. I have two tunnels for IPv4 and IPv6. Flat-1 allows the simulation out to the real world for TFTP. I also changed up my loopback address to /128.