I am working on a new network deployment, and have run into an interesting question... Should the OSPF area 0 be extended across a WAN's point to point links (thereby creating more border routers), or should one's WAN Aggregation router serve as the ABR for each area? Consider the following:
In Scenario 1, R2, assuming area 1 is a totally stubby area receives only a default route, thereby reducing WAN bandwidth... I think? In Scenario 2, R2 receives many more routes. This seems like a trivial question, but I feel it may have a performance impact at scale.
What is the best practice for extending area 0 across a WAN?