DMVPN with OSPF

So I re-did my DMVPN lab and this time I used OSPF on the internal network.  At first, before the tunnels were built, there was nothing spectacular happening.  Even when I built the first tunnel, it all worked pretty good.  Issue can when I added the second tunnel.  All hell starting happening.  The hub was flapping every few seconds.  I couldn't figure out why.  I thought I messed up and I kinda did and didn't.  After some Google searches, I realized that I needed to add ip ospf network point-to-multipoint to the tunnel interfaces.   I didn't know that.  I checked the network type to start with and there was the issue.  All the tunnels were point-to-point by default.  I changed them over to point-to-multipoint and the flapping stopped.

I got to thinking about my issue and it makes sense all the way around.  Tunnels are typically from one location to one location.  A point-to-point tunnel.  Makes sense that the default OSPF network type is the same.  So with only one spoke, everything would work like a charm.  Add another spoke and this is no longer a point-to-point link but since the network type is, the older neighbor is dropped causing it to re-register and this causes the other one to drop.  Well with three neighbors, my hub went nuts and started to drop and come back every couple seconds and ran the CPU up all the way.  Thank goodness it settled once I changed the network type.

Changing the network type did fix my flapping issue but I looked at a spoke and noticed that all my routes had the hub as the next hop.  That made my DMVPN only work in phase 1.  Not cool because that meant that I would have no spoke to spoke traffic.  I pulled out some OSPF notes that I had and found what I needed to fix it.  I changed the network type to broadcast.  I also for safety set the spoke OSPF priority to 0.  Once all this was done, each route had the correct next hop router and DMVPN phase 2 was a go.  Whew!!! 

I tested full connectivity after all this and it all worked.  I was so glad.  I learned quite a bit from doing this and I want to run BGP and RIP over DMVPN now to see how they act.  Figure that with RIP I will have to turn off split horizon.  Have to see what else  is needed.

Here again is my network diagram.