Almost all articles describing DMVPN in combination with OSPF use the “magic” ip ospf database-filter all out command on the hub routers to minimize the OSPF traffic traversing the DMVPN part of the network.
The same trick can be used in any hub-and-spoke network, including Frame Relay-based networks.
What these articles usually fail to tell you is the true impact of this command: it stops all OSPF flooding from hub router. The spoke routers receive no OSPF information whatsoever; to establish connectivity to the network core, you have to use static default routes on the
I’ve described the details of OSPF flooding filters and their use in hub-and-spoke networks in the “OSPF flooding filters in hub-and-spoke environment” article in the CT3 wiki.