RE: Interesting EIGRP Scenario

So the internal from the tunnel is lost. But the external from the bgp to
eigrp redistribution is now presented as an internal. I've seen where the
internal is received on the BGP router, and the BGP route never gets
installed, so you have to configure a weight on the BGP learned routes to
override the EIGRP Internal. I've seen where you want to prefer the EIGRP
External, so you have to configure a distance for the EIGRP Internal to less
preferred then the External.

David

--
http://dcp.dcptech.com
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Laidlaw, Patrick A.
> Sent: Monday, June 13, 2011 8:37 PM
> To: Cisco certification
> Subject: Interesting EIGRP Scenario
> 
> 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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