From: Mahmud, Yasser (YMahmud@Solutions.UK.ATT.com)
Date: Mon Oct 14 2002 - 22:11:13 GMT-3
A BGP router accepting IBGP routes needs to go through the synchronization
process for the incoming IBGP routes
Once it has gone through this process successfuly for these incoming routes
then it can install them in it's routing and if reqd can advertise them out
as EBGP routes OR if reqd as IBGP routes (if acting as a route-reflector)
For the router to go through the synchronization process successfully for
incoming IBGP routes either
1) turn off synchronization on the router
2) It needs to see the same update in its routing table via an IGP.
HTH
Yasser Mahmud
-----Original Message-----
From: D. Lee [mailto:dongweylee1@attbi.com]
Sent: Tuesday, October 15, 2002 12:42 AM
To: Mahmud, Yasser
Cc: ccielab@groupstudy.com
Subject: Re: Help with Local Preference
Thank you, and you are right. Why is that??
I knew the internal route from IBGP peer is not synchronized when I checked
it with sho ip bgp x.x.x.x.
----- Original Message -----
From: "Mahmud, Yasser" <YMahmud@Solutions.UK.ATT.com>
To: "'D. Lee'" <dongweylee1@attbi.com>
Cc: <ccielab@groupstudy.com>
Sent: Monday, October 14, 2002 3:50 PM
Subject: RE: Help with Local Preference
> It seems as a synchronization problem, use the <no sync> command on R2
>
> Yasser Mahmud
>
> -----Original Message-----
> From: D. Lee [mailto:dongweylee1@attbi.com]
> Sent: Monday, October 14, 2002 10:08 PM
> To: Cristian Henry H; Paglia, John (USPC.PCT.Hopewell)
> Cc: 'Peter van Oene'; ccielab@groupstudy.com
> Subject: Re: Help with Local Preference
>
>
> I do not know what I am missing, but it seems like it always prefers the
> external route in my lab.
> (Even though the internal route with a higher local preference)
>
> ----- Original Message -----
> From: "Cristian Henry H" <chenry@reuna.cl>
> To: "Paglia, John (USPC.PCT.Hopewell)" <JPaglia@NA2.US.ML.com>
> Cc: "'Peter van Oene'" <pvo@usermail.com>; <ccielab@groupstudy.com>
> Sent: Monday, October 14, 2002 2:33 PM
> Subject: Re: Help with Local Preference
>
>
> > Also it is propaged troughout an Confederation!
> >
> > "Paglia, John (USPC.PCT.Hopewell)" wrote:
> > >
> > > Local pref propogates throughout an AS, so with all things equal it
> should
> > > go thru r2.
> > >
> > > > -----Original Message-----
> > > > From: Peter van Oene [SMTP:pvo@usermail.com]
> > > > Sent: Monday, October 14, 2002 3:55 PM
> > > > To: Cristian Henry H
> > > > Cc: ccielab@groupstudy.com
> > > > Subject: Re: Help with Local Preference
> > > >
> > > > Pref should override this.
> > > >
> > > > At 04:14 PM 10/14/2002 -0300, Cristian Henry H wrote:
> > > > >Externals first, then internals
> > > > >
> > > > >"D. Lee" wrote:
> > > > > >
> > > > > > R1 and R2 are IBGP peers within the same AS, and they are both
> EBGP
> > > > peering
> > > > > > with other AS.
> > > > > >
> > > > > > A route-map for local preference was created on R2 for a
> destination
> > > > X.
> > > > > >
> > > > > > R1 learned a route to X via his EBGP peer, and it was assigned a
> local
> > > > > > preference 100.
> > > > > > R2 also learned a route to X via his EBGP peer, and it was
> assigned a
> > > > > higher
> > > > > > local-pref 200
> > > > > > because of using the route-map. R2 passed the route with higher
> > > > > local-pref to
> > > > > > R1.
> > > > > >
> > > > > > >From the point of view of R1, the best path to X is through his
> EBGP
> > > > > peer or
> > > > > > R2??
> > > > > >
> > > > > > The router will prefer its external route or its internal route
> with
> > > > higher
> > > > > > local preference??
> > > > > >
> > > > > > Thanks for all the feedback ...
> > > > >
> > > > >--
> > > > >Cristian E. Henry
> > > > >REUNA
> > > > >
> > > > >E-mail: chenry@reuna.cl
> > > > >Fono: 56-2-3370336
> >
> > --
> > Cristian E. Henry
> > REUNA
> >
> > E-mail: chenry@reuna.cl
> > Fono: 56-2-3370336
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