Dual-Hub Dual-ISP DMVPN

[uranthaci]

Dear All,

I'm currently designing a DMVPN topology which includes every branch having 2 different ISP's ( One is L3 and the other one is L2VPN ).

Both Hub's got 2 ISP connections as well, both Hub's will be used although no load balanace  will be done, one will be primary for Data and VoIP ( Hub1 ) and the other one for Internet ( Hub2 ), if one Hub fails, of course the traffic will be routed through the Alive Hub no matter the Hub's primary network.

So far, i've come to this conclusion, i will connect both hubs to a stack switch, instead of connecting them directly to the core layer.

But what i'm trying to accomplish seems a little more difficult than i've thought.

The spoke will always route the data traffic through Hub1 ( to simplify routing on the stack switch ).That means if ISP1 fails, it will register to Hub1 again through ISP2.

Has anyone come across this DMVPN design?

Any pointers would be much appreciated.

Regards,

Uran

[Bastien Migette]

You can either have one DMVPN network and let routing protocols choose if you should use ISP1 or 2 to reach the hub from spokes, or have 2 DMVPN network in overlay (2 tunnel interfaces/tunnel key/...) on each router, and let routing choose which DMVPN you would use.

Have a look at this:

http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/DMVPN_2_Phase2.html#wp37393

[uranthaci]

Thanks for the link, though I can't find my topology there because they use both hubs for all the branches, or just a simple fail-over Hub.

What i'm saying is, I want the Data and VoIP subnet to go through Hub1 always ( Except if Hub1 goes down for technical reasons ) , and the Internet subnet to go through Hub2.So when i'm at the stack switch, I will see only a few summary routes.

What i'm trying to accomplish is, I want to summary routes for example 192.168.0.0/16 ( Data and VoIP ) and 192.169.0.0/16 ( Internet ) down to the stack switch , also at the branches to shorten the routing table.I accidentally redistributed a summary route to the branch router, and I actually liked it.Because that way , the branch router won't have thousand of routes in its routing table, instead it will have only 2 summary routes, one for 192.168.0.0/16 and one for 192.169.0.0/16.

On my current lab configuration i have 4 Tunnels configured on the branch router, and 2 Tunnels on each Hub.

Let me explain the 4 Tunnels..

Tunnel0 is primary for Data and VoIP traffic, it has its Bandwidth set to 5000 and a delay of 1000.Tunnel0 points to HUB1 via ISP1.

If ISP1 goes down on the branch router, Tunnel1 should come up , which points at HUB1 , but via ISP2.I've set Tunnel1 bandwidth to 3000 and delay to 1050, so that way I can seperate T0 and T1 from each other and not load balance.

Now here comes the 2nd part, theres T2 and T3 as well, which does the same thing as T0 and T1 , except its routing for the Internet traffic.

And when T0 goes down, T1 is up but with a higher metric ( because of its delay and bandwidth ) , while T2 has its bandwidth set to 5000 and delay to 1000, it becomes primary  , which I dont like at all.

It's all about logic, but I can't find the right logic for this now.

I hope you understood the topology.

Cheers

Uran

[uranthaci]

I appreciate if anyone could give me some advice on this matter, i think i'm quite close to finishing the lab but a small push would help me very much.

Thanks