Dynamic Multipoint VPN (DMVPN) and IGP Routing Protocols

Dynamic Multipoint VPN (DMVPN) is a multipoint GRE-based tunnelling technology. DMVPN consists of one or more hub routers that are configured as Next-Hop Resolution Protocol (NHRP) Next-Hop Servers (NHS). NHS, or hubs, are used to create mappings between the public IP address used for the tunnel source (NBMA address), and the private IP address used inside of the tunnel (tunnel address).