MPLS VPN support for EIGRP

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Apr 24th, 2009
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http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/fteipece.html


this is configured on PE routers, however most of our providers for our customers are reporting they do not support it. Aside from buidling DMVPN tunnels over the MPLS network to all my locations, is it possible to configure this solution on our CE routers?

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Giuseppe Larosa Fri, 04/24/2009 - 11:43
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Hello Glen,

what you can do is to use eBGP between PE and CE


Be aware that for the different AD of EIGRP external routes in comparison to internal routes the above solution don't support back door links between sites:


if there are direct links between the VRF sites the risk is that they are preferred over the primary links via the MPLS VPN providers.


if there are no direct links you can use eBGP to peer with providers and you can redistribute BGP into EIGRP.

for advertising the local routes of each site I would use network commands under the BGP router process to avoid the complexities and risks of mutual redistribution.


This is a quite common design used by several enterprises.

I would avoid to use DMVPN over MPLS if the reason is only to build a single EIGRP domain.


Note:

other providers may ask for a greater fee to implement EIGRP between PEs-CEs because of increased complexity and usage of additional resources (the VRF address-families in EIGRP).




Hope to help

Giuseppe


glenthms Fri, 04/24/2009 - 15:45
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Thanks Guiseppe. I've brought this up before in prior postings for which you replied already. The EIGRP PE-CE was a solution we have tried to push with the providers but they don't do it. I am limited to EIGRP due to our data center configuration. Our spokes use the MPLS eBGP path to our HQ where we have a VPN tunnel for datacenter traffic. However if that fails, the spokes have their own vpn tunnels which can only run eigrp. This is becoming a big problem and I've pushed for solutions, however its become mismash of configs to make this work. Were running 2 instances of EIGRP on the spokes and redistributing from one EIGRP into another so that the advertisement up the backup tunnel to the data center shows up as 170 EIGRP. The HQ VPN tunnel is also running EIGRP. THe spokes and hub talk over eBGP and we redistribute back into EIGRP. Its a mess. The EIGRP PE-CE is the only solution that seems clean and viable however noone wants to do it.


So 1 we can either redistribute between EIGRP to change the admin distance, or run a tunneling solution over the MPLS eBGP network to preserve EIGRP administrative distances.


Give me a route-map Cisco!!! :D

Giuseppe Larosa Sat, 04/25/2009 - 02:18
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Hello Glen,

the spokes support BGP they use eBGP over the MPLS links.


I don't understand when you say


>> the spokes have their own vpn tunnels which can only run eigrp


I guess you have a GRE tunnel carried inside IPSEc packets.


I would consider to use eBGP also over the GRE tunnels.


Hope to help

Giuseppe


glenthms Sat, 04/25/2009 - 05:36
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All sites that have GRE IPSEC tunnels have to run EIGRP as that's what the data center runs. The spokes have backup IPSEC+GRE tunnels to the Data centers and EIGRP runs across this. Data center won't run BGP to customer sites. That's where I am stuck. I can force the EIGRP admin distance to 170 up to the data center by redistributing from EIGRP into EIGRP but again this is messy and redistribution makes me ill. :D


So yea, I'm really stuck right now on what I can do.


I am also trying to somehow tag routes from my backup tunnel at the hub so I can deny those routes at some spokes but not others. Since the MPLS connected router runs EIGRP and BGP trying to figure out how to tag routes on the backup tunnel when they come in, then tage them again when redistributed into BGP from the hub to the spokes. I want to deny these backup routes for some spokes but not others and dont know how.

Giuseppe Larosa Mon, 04/27/2009 - 00:26
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Hello Glen,


>> All sites that have GRE IPSEC tunnels have to run EIGRP as that's what the data center runs


I understood you have one or a pair of front end routers for the datacenter running only EIGRP.

What if you add two nodes one for the primary tunnels and one for the secondary tunnels that use BGP towards the remote sites and EIGRP towards the datacenter ?

the node terminating primary tunnels will redistribute into EIGRP with a better seed metric.

At the same time the remote site will have an higher BGP weight for the session on the primary tunnel/MPLS link.



The suggestion is to concentrate complexity on the datacenter to make configuration of remote sites simpler and manageable.


About last question


you can use

match tag value

set metric


notice:

set metric value for BGP


set metric value1 value2 value3 value4 value5


for EIGRP

value1 is BW, value2 is delay last value5 is mtu


so you can use

set metric 10000 1000 255 1 1500


to have a bigger metric you can increase delay

set metric 10000 2000 255 1 1500


or you can decrease the BW seed value


you can also add other set actions including set tag in the same route map clause.


Hope to help

Giuseppe


gjstem Sat, 05/02/2009 - 08:15
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Sprint supports EIGRP on their Global L3VPN product. Cisco's BGP cost community implementation with EIGRP works pretty well in terms of minimizing routing loops but convergence/transient loop conditions can still be an issue without appropriate filtering when backdoor routes are involved. EIGRP SoO on the PEs was not supported when I worked over there thus requiring you to still utilize route tagging and filtering on the CE side.

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