A client complained that when their hub router died, all the spokes in their DMVPN hub and spoke topology all lost their tunnels.
The spokes are supposed to be leveraging NHRP to build a database of other spokes' public interface addresses so that they can bypass the hub router for spoke-to-spoke communication.
It seems that that functionality did not work.
What I am suspecting is that the NHRP database entries eventually timeout and require the hub to refresh their databases. Is that true? Do the entries in the NHRP databases timeout? If so, is this configurable?