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Enthusiast

DMVPN as Backup to MPLS

Hello Experts,

I am totally new to MPLS.....

We have 3 location in Asia region(Only 2 in diagramm as a sample) and all location are working with DMVPN means One site as HUB and rest as spokes.

Now we want to implenet MPLS from each location to HQ.

 

 

 Info:

1. Each location has a tunnel to HQ via Internet (We are using eigrp protocol)

2. Now we will have a mpls connection from each location to HQ as primary connection.

 

Future Scenario:mpls_routing1.PNG

 

 

 

Question:

 

How routing will work!!!  could you please give me a sample config!!!!!!

 

Thanks in advance

 

8 REPLIES 8
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VIP Expert

Hello,

 

at first glance, the easiest way to provide for backup routing is to either use a different routing protocol for the DMVPN backup links, or static routes with higher distances.

So if you use internal EIGRP (90), you could use either OSPF (110) or RIP (120). If you use external EIGRP (170), you could use static routing (with admin distance of e.g. 200).

That said, can you post the configs of the hub and one of the remote sites ?

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Thanks for quick resposnse.

MPLS is not active at the moment!!!

HUB and spoke config: Please find the attached text file.

 

Thanks

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My suggestion is to use EBGP for your MPLS at the remote sites and at the HUB.

 

If you use EIGRP over DMVPN that distance is 90 and if you use EBGP with the PE (provider edge) on the MPLS that distance is 20. 

 

If the router has both routes via DMVPN and MPLS the BGP routes will be in the routing table and the EIGRP will be in the topology but not in the routing table until the EBGP route have gone missing.

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Here is also a quick view of what the routing could look like if you are terminating the MPLS and DMVPN on the remote router. (I made up some networks to represent wan connections so this might not apply but I focused on the 172.24.50.0/29 to route this network over EIGRP and EBGP) As you can see the end result is the route is learned via EBGP but the route made it via EIGRP.  I ran a debug and shutdown the interface on MPLS and the route then was learned via EIGRP.

 

Spoke(config-if)#do sh ip bgp
BGP table version is 14, local router ID is 75.75.75.6
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  65.65.65.0/30    65.65.65.5               0             0 2 i
 r>  65.65.65.4/30    65.65.65.5               0             0 2 i
 *>  172.24.50.0/29   65.65.65.5                             0 2 1 i


Spoke(config-if)#do sh ip ei top
EIGRP-IPv4 Topology Table for AS(1)/ID(172.25.56.52)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 172.24.50.0/29, 0 successors, FD is Infinity
        via 172.25.56.56 (27008000/128256), Tunnel56
P 172.25.56.0/24, 1 successors, FD is 26880000
        via Connected, Tunnel56
        via 172.25.56.56 (27136000/25856000), Tunnel56

Spoke(config-if)#do sh ip route | in 172.24.50
B        172.24.50.0 [20/0] via 65.65.65.5, 00:01:07

 

<------------------------------------------------->

Spoke(config-if)#int g0/0
Spoke(config-if)#shut
*Dec  5 10:06:28.315: RT: del 172.24.50.0 via 65.65.65.5, bgp metric [20/0]
*Dec  5 10:06:28.319: RT: delete subnet route to 172.24.50.0/29
*Dec  5 10:06:28.355: RT: updating eigrp 172.24.50.0/29 (0x0):
    via 172.25.56.56 Tu56  1048578

*Dec  5 10:06:28.359: RT: add 172.24.50.0/29 via 172.25.56.56, eigrp metric [90/27008000]

 

Spoke(config-if)#do sh ip route | in 172.24.50
D        172.24.50.0 [90/27008000] via 172.25.56.56, 00:01:55, Tunnel56

 

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Thanks for your answer...

 

MPLS router is handled and supported by provider so i cant say which routing protocol they will use!!!

 

How I should conifgure my router  so that primary link is MPLS and backup as DMVPN over eigrp.

 

Thanks

 

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Hi ittechk4u1,

Normally you as the client has some say on how the router is going to be configured that sits on the customer edge network/ location.  With that said I would still run EBGP with your DMVPN router and the service provider router that is sitting on your network on your LAN.  If that is not an option then you might want to consider static routing with an IP SLA and object tracking.  The IP SLA will be used to monitor a remote IP on the WAN for example via the service provider router and the object tracking will be used to tie it to the static route.   Since you already are running EIGRP that route will get used if the tracked object is not available. 

 

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Static router -- Its my 2nd option

 

As I am using

Eigrp -. for DMVPN  and i hope serive provider will use ...EBGP - for MPLS

 

Do i need to redistribute EIGRP in BGP and BGP in EIGRP ?

Could you please provide me the sample config of EBGP on my router and MPLS router. and how can i redistributte it .

 

Thanks

 

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Hi, 

If you are learning the same routes via DMVPN (EIGRP) and MPLS (EBGP) on the same router you should not need to do any redistribute of any protocols since all needed routes are on both routing domains and this is only a spoke.

 

Here is a sample config

 

Spoke#show run | sec router eigrp
router eigrp 1
network 172.25.56.52 0.0.0.0
passive-interface default
no passive-interface Tunnel56
Spoke#
Spoke#
Spoke#show run | sec router bgp
router bgp 65000
bgp log-neighbor-changes
network 65.65.65.0 mask 255.255.255.252
timers bgp 15 30
neighbor 65.65.65.5 remote-as 2