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DMVPN and NHRP Routing

bill.greenwood
Level 1
Level 1

I am using DMVPN with EIGRP to provide mostly a backup path to an MPLS network using BGP. However the network is a mixture of sites that are connected to both the MPLS and Internet based DMVPN network and sites that are only connected to the DMVPN network (no MPLS connection). This is where the problem becomes apparent; the DMVPN only sites do not get a direct route to other remote sites that have both DMVPN and MPLS connections. At the headend the better route will be through the MPLS network. The DMVPN head end is on the same device that terminates the MPLS network and due to this will not sent the direct route via EIGRP so traffic from the DMVPN only site routs traffic to the headend across the MPLS network to the remote site. While the remote site sends it return traffic directly across the DMVPN as there is no MPLS route so the DMVPN headend sends the direct route.

I have been able to overcome the problem of the headend not sending the direct EIGRP routes when it has a BGP (MPLS) route by configuring neighbor statements under EIGRP allowing the remote sites to learn to direct route across the DMVPN. My concern is two fold; one this doesn't scale very well as all sites need a neighbor statement for all other remote sites and two the impact of the unicast neighbor communication to all other remote sites.

My question: is there another way to solve the problem of the remote site not receiving the direct route from the headend? It is not possible to separate the headend DMVPN from the MPLS. A secondary question is what other problems can this create.

Thanks for your input.

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2 Replies 2

Jeff Van Houten
Level 5
Level 5

Why not run bgp for both MPLs and DMVPN?

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I have thought about that, but I don't believe running BGP over the DMVPN will solve the problem as the headend router will still need to prefer the MPLS route.

Bill

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