30: Dynamic Multipoint Virtual Private Network (DMVPN)
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________
© Virtual Access 2018
GW2020 Series User Manual
Issue: 2.1
Page 313 of 423
30.3
DMVPN scenarios
30.3.1
Scenario 1
Spoke1, spoke2 and a hub are in the same public or private network.
Figure 150: Network diagram for DMVPN spoke to spoke
•
Spoke1 and spoke2 connect on their WAN interface: ADSL, 3G and initiate main
mode IPSec in transport mode to the hub.
•
After an IPSec tunnel is established, spokes register their NHRP membership with
the hub.
•
GRE tunnels come up.
•
Hub caches the GRE tunnel and real IP addresses of each spoke.
•
When spoke1 wants to talk to spoke2, it sends an NHRP resolution request to the
hub.
•
The hub checks its cache table and forwards that request to spoke2.
•
Spoke2 caches spoke1’s GRE and real IP address and sends an NHRP resolution
reply via the hub.
•
Spoke1 receives an NHRP resolution reply and updates its NHRP table with
spoke2 information. Then it initiates VPN IPSec connection to spoke2.
•
When an IPSec tunnel is established, spoke1 and spoke2 can send traffic directly
to each other.