From: Venkataramanaiah.R (vramanaiah@gmail.com)
Date: Thu Nov 24 2005 - 10:47:37 GMT-3
Agree, Tunnel sounds like a good idea to avoid redistribution of BGP
table. Never thought about this before..
However, i do not understand the issue that you have with the tunnel
i/f.. R u saying the tunnel keeps flapping? Then make tunnel interface
as passive. it would then never run eigrp on it and the chicken/Egg
story will be stopped..
-Venkat
On 11/24/05, Anthony Sequeira <terry.francona@gmail.com> wrote:
> Hi Leigh!
>
> Errr - take another look - R1 and R4 are running iBGP with each other -
> setting NEXT-HOP-SELF on the peering from R1 to R4 will have no effect.
> Since R4 must use R2 to reach R1 - traffic will still be black-holed at R2.
>
>
>
> On 11/24/05, Leigh Harrison <ccileigh@gmail.com> wrote:
> > Hey there Anthony,
> >
> > If you don't want to redistribute bgp into igp (not that popluar with
> > me!), then you could pop in "next-hop-self".
> >
> > This way the next hop for the destinations can be found via the igp. No
> > redistributing required. :)
> >
> > LH
> >
> > Anthony Sequeira wrote:
> >
> > >Hi *Venkataramanaiah.R!*
> > >You are correct in that we do not need a tunnel for the iBGP peering to
> work
> > >between R1 and R4 through R2. As you know - the iBGP peerings do not need
> to
> > >be direct connections. The issue will come later with reachability. For
> > >example - if we advertise a prefix into BGP on R1 - R4 will not have
> > >reachability due to a "black-hole" situation on R2.
> > >
> > >I do not want to redistribute BGP into the IGP here - so I wanted to play
> > >with the tunnel option as I describe here.
> > >
> > >
> > >
> > >On 11/24/05, Venkataramanaiah.R <vramanaiah@gmail.com> wrote:
> > >
> > >
> > >>I do not understand the need for tunnel interfaces here for the IBGP
> > >>to work via R2. Am i missing something here?
> > >>
> > >>-Venkat
> > >>
> > >>On 11/24/05, Tim <ccie2be@nyc.rr.com> wrote:
> > >>
> > >>
> > >>>A couple things I noticed:
> > >>>
> > >>>1) The tunnel endpoints should be on R1 and R4, not R2.
> > >>>
> > >>>2) You didn't adjust the cost of the tunnel to make it less preferred
> > >>>
> > >>>
> > >>path
> > >>
> > >>
> > >>>than the physical path.
> > >>>
> > >>>3) I would use the physical interface as the tunnel source on each
> > >>>
> > >>>
> > >>router.
> > >>
> > >>
> > >>>4) If using the lo0 for the tunnel ip address doesn't work, you can
> try
> > >>>using the ip address of the physical interface for the tunnel address.
> > >>>
> > >>>Just a couple ideas,
> > >>>
> > >>>Tim
> > >>>
> > >>>-----Original Message-----
> > >>>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > >>>Anthony Sequeira
> > >>>Sent: Wednesday, November 23, 2005 9:42 PM
> > >>>To: Cisco certification
> > >>>Subject: Let's Tunnel BGP Due to Non-BGP Speaker in Transit Path!
> > >>>
> > >>>I want to tunnel my iBGP peering from R1 to R4 because R2 is not
> running
> > >>>BGP. I want to use the loopback 0 interfaces for the peerings. The IGP
> > >>>
> > >>>
> > >>in
> > >>
> > >>
> > >>>use is EIGRP and all of the interfaces shown below are running EIGRP.
> > >>>
> > >>>
> > >>>
> > >>>R1-----4.4.8.0 /24-----R2-----4.4.12.0/24-----R4
> > >>>
> > >>>
> > >>>
> > >>>R1 lo0 4.4.1.1/24
> > >>>
> > >>>R4 lo0 4.4.4.4/24
> > >>>
> > >>>
> > >>>
> > >>>I have this sample scenario labbed up and I am having a heck of a time.
> > >>>
> > >>>
> > >>I
> > >>
> > >>
> > >>>have tried the following with no luck:
> > >>>
> > >>>
> > >>>
> > >>>Attempt 1
> > >>>
> > >>>R1:
> > >>>
> > >>>int tunnel 0
> > >>>
> > >>>ip unnumbered lo0
> > >>>
> > >>>tunnel source 4.4.8.1
> > >>>
> > >>>tunnel destination 4.4.12.4
> > >>>
> > >>>
> > >>>
> > >>>R2:
> > >>>
> > >>>int tunnel 0
> > >>>
> > >>>ip unnumbered lo0
> > >>>
> > >>>tunnel source 4.4.12.4
> > >>>
> > >>>tunnel destination 4.4.8.1
> > >>>
> > >>>
> > >>>
> > >>>Attempt 2
> > >>>
> > >>>R1:
> > >>>
> > >>>int tunnel 0
> > >>>
> > >>>ip unnumbered lo0
> > >>>
> > >>>tunnel source lo0
> > >>>
> > >>>tunnel destination 4.4.4.4
> > >>>
> > >>>
> > >>>
> > >>>R2:
> > >>>
> > >>>int tunnel 0
> > >>>
> > >>>ip unnumbered lo0
> > >>>
> > >>>tunnel source lo0
> > >>>
> > >>>tunnel destination 4.4.1.1
> > >>>
> > >>>
> > >>>
> > >>>You see this is easy and works great if I create a new subnet for the
> > >>>tunnel and use that in my BGP peerings the issue that I am having is
> > >>>trying to use the loopback addresses for the peerings and still use my
> > >>>tunnel.
> > >>>
> > >>>
> > >>>
> > >>>I notice that my tunnel interface does not show up in the routing table
> > >>>
> > >>>
> > >>when
> > >>
> > >>
> > >>>I am pulling the address from the loopback..I guess this must be why
> my
> > >>>
> > >>>
> > >>BGP
> > >>
> > >>
> > >>>is not using it????
> > >>>
> > >>>
> > >>>
> > >>>Anyone feel like labbing this one up and trying this one? Or is it
> > >>>
> > >>>
> > >>something
> > >>
> > >>
> > >>>really simple that I am missing about tunnels?
> > >>>
> > >>>
> > >>>
> > >>>Thanks in advance for you consideration of this e-mail.
> > >>>
> >
> >>>_______________________________________________________________________
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> >
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> >
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