I read the following, under the OSPF section on Frame Relay implementation of my CCNP Route studies:
"In a frame relay topology of hub router to branch router, where the branch has two routers for redundancy, and the WAN links from said routers back to the hub have different frame relay CIR's, the recommended way of controlling that OSPF always takes the path with the higher CIR is to set the network type to point-to-multipoint and configure static neighbors on the hub router and give each a cost."
So, understanding that, what would happen in the case that I had a point-to-multipoint hub and spoke network like above, but instead of frame relay, I am using DMVPN, and the broadband circuit on branch router 1 is 6Mbps while the broadband circuit on branch router 2 is 1.5mbps? If I wanted to make sure the 6mbps circuit was always preferred, would I have to set the hub router network type to point-to-multipoint on the hub, configure the static neighbors and assign a cost on the hub for each spoke router in the branch, just as they recommend for OSPF over frame relay?
Additionally, for the sake of the concept, assume HSRP/VRRP can't be used please.
If I wanted to make sure the 6mbps circuit was always preferred, would I have to set the hub router network type to point-to-multipoint on the hub, configure the static neighbors and assign a cost on the hub for each spoke router in the branch, just as they recommend for OSPF over frame relay?
Yes, that would be necessary. You see, a hub router has a single GRE multipoint interface to talk to all spokes. Therefore, configuring an OSPF cost on this interface would apply summarily to all spokes. What you want to achieve, though, is a per-neighbor OSPF cost. In the case the neighbors are reachable over a single interface, the only way of doing this in OSPF is to configure the OSPF network type to point-to-multipoint non-broadcast and define all spoke neighbors statically along with their intended costs. Please note that the network type must include the non-broadcast keyword, as the neighbor command is only accepted for neighbors over a non-broadcast network type.
Spoke routers would also need to use the point-to-multipoint non-broadcast network type, and refer to the hub router using the neighbor command, again with the indended cost.