From: Timothy Chin (Tim@1c-solutions.com)
Date: Fri Mar 07 2008 - 21:59:19 ARST
The Default Local Preference on all routers in the same AS is 100. The
reason why the router is selecting the EBGP route over the IBGP route is
because the Local Preference values are the same. If you were to set a
higher local preference on one of the routers then the IBGP route to the
router with the higher Local Preference would be selected. The last step
in the BGP path selection process is to select the EBGP route over the
IBGP route:
1) Weight (Highest)
2) Local Preference (Highest)
3) Locally originated
4) Shortest AS Path
5) Origin code
6) MED (lowest)
7) Prefer EBGP route over IBGP
There are a few steps that have been left out but these are most
important - In that order.
Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Hash Aminu
Sent: Friday, March 07, 2008 12:46 PM
To: dave dave; Cisco certification
Subject: Re: Confusion on BGP route selection
Check the AD of the two routes .....which one is suppose to be
seslecyed?
On 3/4/08, dave dave <funccie@gmail.com> wrote:
> Hi Expert,
> As in below example i am running only BGP, the route 155.1.5.0/24
learning
> from AS-1 EBGP peer as well as IBGP peer, but my router selecting EBGP
learn
> route as best route over the IBGP.
>
> As per my understandig IBGP shpuld be BEST route for 155.1.5.0/24
because
> of highest LOF of IBGP is 100 (heigest prefer) preferable over EBGP.
>
> #R1 (belong to AS 2)
> Network Next-Hop Metric LocPrf Weight
Path
> * i155.1.5.0/24 155.1.13.3 0 100 0
> 1 i
> *> 155.1.146.4
> 0 1 i
>
> Please clear my confusion on above.
>
> Regards
> Dave
>
>
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