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DMVPN - Using 2 Different ISP Circuits for Spoke Tunnels

Hi, anybody tried this.?

We have a DMVPN - Dual Hubs (7206) in our data centre. The Spoke sites normally have 1 * ADSL/SDSL ISP link and the 2 tunnels are configured to run down this one ISP circuit - one tunnel to each of the hub routers and all works ok. We use BRI ISDN as backup.

However, some sites now want to use a separate ISP circuit instead of the ISDN backup. So, this will mean running tunnel-1 down one ISP link and tunnel-2 down the other. Both ISP circuits will be sourced from different carriers.

Has anyone done this - is it just a simple case of creating another Dialer interface for the 2nd ISP link and specifying 'tunnel source dialer0' on tunnel-1 and 'tunnel source dialer1' on tunnel-2.?



Re: DMVPN - Using 2 Different ISP Circuits for Spoke Tunnels

Each spoke has a permanent IPSec tunnel to the hub, not to the other spokes within the network. Each spoke registers as clients of the NHRP server.

When a spoke needs to send a packet to a destination (private) subnet on another spoke, it queries the NHRP server for the real (outside) address of the destination (target) spoke.

After the originating spoke learns the peer address of the target spoke, it can initiate a dynamic IPSec tunnel to the target spoke.

The spoke-to-spoke tunnel is built over the multipoint GRE interface.

The spoke-to-spoke links are established on demand whenever there is traffic between the spokes. Thereafter, packets are able to bypass the hub and use the spoke-to-spoke tunnel

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