DMVPN Load Balancing

[michal.grzelak]

I am trying to find a solution to load balance traffic in DMVPN ( 200+ branches )solution where branch with 2800 router has two ISP connections that connects to two HUB routers ASR 1k. I want to achieve that some applications uses one WAN link and all other on another WAN link.

There is no problem with load balancing traffic from branch to hub using routing metrics, etc, but i am stuck with idea how to get traffic back to branch using the same ISP connection.

Has anyone had the same problem and found any way to solve it?

[uranthaci]

Hi Michal,

Yes, it is possible and I am currently using that hierarchy on my network.

My DATA Vlan uses ISP1 , while INTERNET uses ISP2.

I have 2 Hub's on my HQ, each HUB has 2 Tunnels with 2 ISP providers, and the branches have 4 Tunnels ( 1 Tunnel primary for DATA via ISP1 through HUB1, 1 Tunnel secondary for DATA via ISP2 through HUB2, and the same goes for INTERNET vlan just that INTERNET vlan has ISP2 as it's primary link, in order not to overload ISP1 and utilize both links at the same time).

The Hub's do the splitting of the traffic, I'm using Offset-list ( EIGRP ) to order the traffic going for DATA via ISP1 and INTERNET via ISP2, and then as for the returning traffic I am using summarization on the Hub's Tunnels, you could define your internal vlans with a smaller metric on your primary ISP Tunnel, while increasing your internal vlans metric via your secondary ISP Tunnel and lowering the metric for 0.0.0.0/0 subnet ( which defines everything else, in this case, the INTERNET ).

It may be overwhelming in the beginning , and it took me some time to implemenet this, but I have to say it was worth every minute i've spent doing it

Cheers

[michal.grzelak]

Thanks for your answer. Its tricky, but might work. Could you please share your config for hub and one of the spokes.

Is your design and configuration works that traffic for DATA goes out ISP1 to HUB1 and gets back to spoke through the same path?