Dynamic Multipoint Virtual Private Network (DMVPN) [1] is a dynamic tunneling form of a virtual private network (VPN) supported on Cisco IOS-based routers, Huawei AR G3 routers, [2] and Unix-like operating systems.
DMVPN provides the capability for creating a dynamic-mesh VPN network without having to statically pre-configure all possible tunnel end-point peers, such as IPsec and ISAKMP peers. [3] DMVPN is initially configured to build a hub-and-spoke network by statically configuring the hubs (VPN headends) on the spokes; no change in the configuration on the hub is required to accept new spokes. Using this initial hub-and-spoke network, tunnels between spokes are dynamically built on demand without additional configuration on the hubs or spokes. This dynamic-mesh capability alleviates the need for any load on the hub to route data between the spoke networks.[ citation needed ]
Routing protocols such as OSPF, EIGRP v1 or v2 or BGP are generally run between the hub and spoke to allow for growth and scalability. Both EIGRP and BGP allow a higher number of supported spokes per hub. [5]
As with GRE tunnels, DMVPN allows for several encryption schemes (including none) for the encryption of data traversing the tunnels. For security reasons Cisco recommend that customers use AES. [6]
DMVPN has three phases that route data differently.