DMVPN with Dual Hub/Dual ISPs for Hub and Spokes

Unanswered Question
May 19th, 2010
User Badges:


I am working on my first DMVPN project and i would like to have some expert advices.

Here is the topology:

Two Hubs (one in France with Dual ISPs and the other in the US with one ISP for now) and many spokes (60 with two ISPs). Some spokes have to communicate each other directly and access some resources to the US and France Hub. The Hubs have to communicate directly as well.

I read the DMVPN Design guide, but it is oriented towards Dual VPN with single ISP and i would like some help to point me to the right direction.

Many thanks.


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
youssef.el.fathi Thu, 05/20/2010 - 02:46
User Badges:

Hello Andrew,

My question is about design.

If i go with two routers with HSRP and each one attached to each ISP, i will have to build, for a spoke, 4 multipoint GRE tunnels on each router.

I attached a sample design for the clarity.

Is this design correct, easy to implement or i can do it another way?


PS : as stated in the first post, the goal is redundancy of equipment and WAN Access with spoke-to-spoke "direct communication".

Typically this would be true of non-DMVPN tunnels - static GRE.  However with the aid of NHRP you

only need 1 "Tunnel" but you would still need multiple VPN's to and from the seperate ISP IP addresses - but as in the name DMVPN these would be dynamic VPN tunnels anyway!  You just need to configure the NHRP servers!


youssef.el.fathi Thu, 05/20/2010 - 05:05
User Badges:


In summary, as i have two ISPs for the HUBs, i need two tunnels for each HUB, acting as NHRP Servers. But for the spokes, i will have four static tunnels that will learn IP addresses from the previous NHRP servers. Finally we have four subnets IP matching my four DMVPN clouds.


This Discussion

Related Content