RE: Interesting EIGRP Scenario

I want the routes the be preferred in EIGRP but I don't care about which routes wins out on R1 as long as R2 ends up with the correct internal eigrp AD of 90 from R3.

It just seemed weird that the R1 router would add a tag to the internal EIGRP learned routes and keep them propagating instead of replacing them with eigrp external routes when the internal route disappeared.

Patrick

-----Original Message-----
From: James Poplawski [mailto:jb.poplawski_at_gmail.com]
Sent: Monday, June 13, 2011 5:51 PM
To: Laidlaw, Patrick A.
Cc: Cisco certification
Subject: Re: Interesting EIGRP Scenario

Lab it up. What I found was if you want the external routes (bgp
redistro) to be less preferred, create distance command under bgp with
the neighbor tied to an access-list.

Send me a topo and sanitized configs, I ran into something similar and
it sounds familiar to me.

Let me know,
JB

Sent from my iPhone

On Jun 13, 2011, at 8:39 PM, "Laidlaw, Patrick A."
<Patrick.Laidlaw_at_wwt.com> wrote:

> Well members I've been stumping my way through a scenario that has been
> driving me nuts all afternoon.
>
> MPLS cloud and Tunnel cloud .
>
> I had a route that was getting advertised as an internal eigrp network of
> 10.2.4.0/24 over the tunnel preferred route R3. The network was also learned
> over the MPLS BGP neighbor on a different router R1 and redistributed into
> eigrp. R2 would learn the route from R3 as eigrp internal and from R1 as
> eigrp external. R1 R2 and R3 are connected in a triangle.
>
> ROUGH TOPOLOGY:
> /--------------10.1.4.0/24------------\
> / \
> Tunnel R3-gig-R2-gig-R1 MPLS AS200
> \--fastE----/
>
> If R3 ever hiccupped and the Tunnel was down a loop would occur. After the
> tunnel came back up, eigrp would show that R1 advertized the network to R2 as
> Eigrp internal, that R2 advertized the network as eigrp internal on R3, and
> that R3 advertized the network to R1 as eigrp internal.
>
> The weird thing is the route now shows a tag of 200 after the tunnel came back
> up. I could shut this tunnel down again and it would still show everything as
> eigrp internal instead of being advertised as external from BGP to EIGRP on
> R1.
>
> I've got a temporary solution of kicking the Delay way up on the Fast E
> between the R3 and R1 but I'm a bit baffled at this point why or what process
> is going on that would keep the network advertised as eigrp internal and then
> tag it with 200 off the external redistributable route from BGP
>
>
> Patrick Laidlaw - Deployment Engineer
> E: patrick.laidlaw_at_wwt.com<mailto:patrick.laidlaw_at_wwt.com>
>
>
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Received on Mon Jun 13 2011 - 19:55:43 ART