DMVPN Design using ISP Dialup Redundancy at spoke side.

[Riyasat Ali]

I'm working on a new DMVPN configuration with one 3745 at the hub site and a 1941 the spoke. I have internet through gsm for the primary line at the spoke and a dsl line for  backup on spoke.

I have one tunnel interfaces on both the hub and the spoke.Currently my VPN tunnel is coming up fine , however we are planing to do an ISP failover at spoke side . since in the tunnel interface i can only define one "tunnel source interface" which is gsm cellular interface , i don;t know how to use my another ISP for the same tunnel interface as it will always initiate traffic from gsm.

do i have to create another tunnel interface with same hub site , or do i need another hub as backup ?

is their any other way to create loopback interface and initiate the traffic from that loopback ??

Does anyone have any suggestions on how I should design ? or  Does anyone have any idea what the problem might be?

Thanks.

[malshbou · Accepted solution]

Hi,

There are many designs to implement high-availabilty A in DMVPN.  Basically, design decisions depend on the infrastructure, budget, and on whether you are looking to implement HA for DMVPN devices, ISP links, or both.

on your scenario, you seem looking for implementing ISP redundancy for DMVPN HA at the spoke side. This scenario can be achieved by Dual-cloud Single-hub design, also with double-hub it can be more highly available.

The design elements for your scenario:

- two tunnel interfaces using two source physical interfaces in spoke.

- two tunnel interfaces in the hub, they can share the same physical interface.

- Key point: using dynamic routing protocols in the two clouds with different "link costs", so that the primary connection has the lower cost, and the secondary connection has the higher cost (to be used upon failure)

I Hope this helps you

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Mashal Alshboul