33: Dynamic Multipoint Virtual Private Network (DMVPN)
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________
© Virtual Access 2018
GW1000 Series User Manual
Issue: 2.3
Page 349 of 463
33
Dynamic Multipoint Virtual Private Network (DMVPN)
Dynamic Multipoint Virtual Private Network (DMVPN) is a scalable method of creating
VPN IPSec Networks. DMVPN is a suite of three protocols: NHRP, GRE and IPSec, used to
dynamically create VPN tunnels between different endpoints in the network without
having to pre-configure each device with VPN details of the rest of endpoints in the
network.
33.1
Prerequisites for configuring DMVPN
Before configuring DMVPN, you must first configure:
•
A GRE interface; the previous chapter,’ Configuring GRE interfaces’
•
An IPSec connection to use as a template; read the chapter, ’Configuring IPSec’.
33.2
Advantages of using DMVPN
Using DMVPN eliminates the need of IPSec configuration to the physical interface. This
reduces the number of lines of configuration required for a VPN development. For
example, for a 1000-site deployment, DMVPN reduces the configuration effort at the hub
from 3900 lines to 13.
•
Adding new peers (spokes) to the VPN requires no changes at the hub.
•
Better scalability of the network.
•
Dynamic IP addresses can be used at the peers’ site.
•
Spokes can be connected in private or public network.
•
NHRP NAT extension allows spoke-to-spoke tunnels to be built, even if one or
more spokes is behind a Network Address Translation (NAT) device.
•
New hubs can be added to the network to improve the performances and
reliability.
•
Ability to carry multicast and main routing protocols traffic (RIP, OSPF, BGP).
•
DMVPN can be deployed using Activator, the Virtual Access automated
provisioning system.
•
Simplifies branch communications by enabling direct branch to branch
connectivity.
•
Simplifies configuration on the spoke routers. The same IPSec template
configuration is used to create spoke-to-hub and spoke-to-spoke VPN IPSec
tunnel.
•
Improves business resiliency by preventing disruption of business-critical
applications and services by incorporating routing with standards-based IPsec
technology.