From: Mohamed T. Kondela (mtaib@sagia.gov.sa)
Date: Mon May 29 2006 - 14:22:07 ART
Can we apply prefix-list+routemap combination here.? If the question
ask you to make both entries available in BGP table, but prefer one over
other.
Regards
Mohamed T. Kondela
Senior Network Engineer
IT Dept.
Fax: 4473037 x 303
mtaib@sagia.gov.sa
Saudi Arabian General Investment Authority
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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gianpietro Lavado
Sent: Monday, May 29, 2006 7:52 PM
To: Carlos Campos Torres (ccampost)
Cc: loke; Nambi Appachigounder; Krishnadas manghat;
ccielab@groupstudy.com
Subject: Re: Hi,Please help me in a BGP attribute issue
Please clarify; I don't understand why the network is originally
preferred
from IBGP because of the LP, the LP value is the default value (100), so
assuming that the LP is not changed inbound in the EBGP route on R2,
there
would be a tie right? the only attributes that could make the IBGP route
preferred would then be Origin or MED* (a show ip bgp <network> would
help).
Also, if the network was preferred through R4 because of LP as Kayd
said,
then you would not be able to use AS-Path/MED to change the bestpath
selection because this attributes are not evaluated before LP. The
solution
then would be to filter that IBGP network or to make its next-hop
inaccessible (if not able to force weight or LP as stated in the
question).
Please correct me if I'm wrong, thanks!
*Note: Bestpath selection
Weight -> LP -> locally originated -> AS-Path -> Origin -> MED -> EBGP
over
IBGP -> closest IBGP peer -> older EBGP peer -> <Router ID
Gianpietro
On 5/29/06, Carlos Campos Torres (ccampost) <ccampost@cisco.com> wrote:
>
> Yup, I would apply AS Path prepend inbound here if possible.
>
>
> Carlos Campos
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> loke
> Sent: Sunday, May 28, 2006 1:57 PM
> To: Nambi Appachigounder
> Cc: Krishnadas manghat; ccielab@groupstudy.com
> Subject: Re: Hi,Please help me in a BGP attribute issue
>
> Or AS Path Prepend.
>
>
>
> On 5/28/06, Nambi Appachigounder < nambi_gct@yahoo.co.in> wrote:
> >
> > You can either use MED/localpref/weight for this.
> > if you are using med you need to apply the route map in the outbound
> > direction in as1.
> >
> > otherwise in as2 you apply an inbound route map,set the local pref
as
> > per your wish.
> >
> > -nambi
> > --- Krishnadas manghat < krsna83@gmail.com> wrote:
> >
> > > Hi All,
> > > I just have a small question in BGP which i came across
> > > while doing a lab from doit workbook , I have the following setup
> > >
> > >
> > > R1-------R2------R3------R4
> > > I I
> > > ---------------------------------
> > >
> > >
> > > R1 and R4 are in the AS 1 . R2 and R3 are in AS 2
> > >
> > > AS1 is pumping a network to AS2 ,Hence R2 gets the same network
> > > thru R1 and R4
> > >
> > > R2 chooses route coming from the R4 as the local preference is
100
> > > .
> > >
> > > How do i make R2 prefer the route coming from R1 without using
> > > Weight and Local Preference attribute and the configuration should
> > > be done only on R2 .
> > >
> > >
> > > Thanks ,
> > > Kayd
> > >
> > >
> >
This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:22 ART