I have a question about a project that I've finished designing that I'd like some help with.
I've been tasked with redesigning our WAN throughout south and central America. Right now, our infrastructure has 3 circuits to each country, so we have to create 3 GRE tunnels on the Hub router, and 3 GRE tunnels on the Spoke router. Since we have dozens of sites, the amount of static tunnels on the Hub is pretty big.
My project was to design a DMVPN to reduce the number of tunnels across the WAN, and move away from OSPF to BGP to have more control over how the routing over our network happens.
Right now, we have OSPF Area 0 running over our tunnels that connect back to our Hub, and for our local routing inside each site, we have a separate Area, such as Area 73, for example.
My question is this: Since OSPF design requirements say that each area must connect back to Area 0, if I remove OSPF Area 0 and replace it with BGP for WAN routing, am I going to have any routing inconsistencies whatsoever since our example Spoke who is internally running Area 73, no longer has a connection back to Area 0?