This is a Cisco proprietary protocol. The Dynamic Multipoint Virtual Point Network feature allows you to easily scale your enterprise network. Even small companies use DMVPN with IPSec.
DMVPN allows you to configure a single GRE tunnel interface and one IPSec profile on the hub router that would manage all other routers. This feature will automatically create the tunnels for you from hub to spoke or spoke to spoke, making your life a lot easier. It does so with the help of the following protocols:
- NHRP
- Multipoint GRE
DMVPN comes in three phases. I will show a Phase 1 configuration, which is not on the test at all:
hub:
int tunnel0
ip address 10.1.0.5 255.255.255.0
ip nhrp authentication hush
ip nhrp map multicast dynamic
ip nhrp network-id 99
tunnel source gig1.100
tunnel mode gre multipoint
tunnel key 100000
spoke:
interface tunnel0
ip address 10.1.0.1 255.255.255.0
ip nhrp authentication...
