DMVPN is a simple, secure, low cost, scalable VPN-Tunnel. DMVPN supports distributed applications including: data, voice, and video, with QoS. All of this can be done in a secure IPSec VPN tunnel over an Internet connection.  The only change is the IP address of the GRE Tunnel.  The spoke uses dynamic discovery of IPSec tunnel end-points, (other spokes). No IPSec static configuration for each spoke.

Because DMVPN supports multipoint GRE tunneling you can run VoIP, Video, and Multicast services across your secure DMVPN link. Hub-and-Spoke, (H&S) and Spoke-to-Spoke, (S2S). With H&S the design.

It’s a cost effective and secure communication for branch offices.

DMVPN Overview