We have a fairly complex network that we are replacing with an SDN (tunneled over commodity internet) from tik to tik. All of our endpoints have a CCR 1009 or 1016 from which to tunnel to. We are trying to move our corporate Public IP's across the tunnel to the branch offices and then we run NAT with Firewall rules in each branch office. On the existing L2 fiber, we are simply using OSPF to handle failover. between our primary and secondary carrier choices.

We are currently trying to make either Wireguard p2p, or EOIP, or GRE tunnels work for the best throughput however between the two different providers we have at most locations, (usually AT&T ABS or Spectrum/COX fiber or Spectrum/Cox Coax service).

We can make the individual WAN connections work but can't seem to make OSPF failover work automatically. We do see that the Spectrum Coax Provides us with only a 1492MTU, Spectrum Fiber a 1500MTU and COX fiber we get 9214MTU. I am assuming that the MTU and the tunnel type is causing our issue but just haven't figured out what the best combination of tunnel types for mixed sized MTU's is. All of our circuits are 1Gig at the remote sites, and our hub site (this is a hub and spoke network) is fed by 1-100GB feed and 2-10GB providers all with 9000 MTU's and not congestion issues. We are using a ping to the gateway to detect down events.

So looking for thoughts/suggestions on why this isn't happening, recommendations on best tunnel type to use? We are currently using all tunnels as GRE.

SW