From: yakout esmat (yesmat@xxxxxxxxxxxxxx)
Date: Wed Apr 24 2002 - 06:01:20 GMT-3
Irene,
Easy, Local Pref is a value given to routes as they enter the AS and stay
with these routes as they propagate within this AS.
In your example:
1) Route 10.0.0.0 is assigned LocalPref of 200 as it enters AS1 by RA. it
shows in your output 'show ip bgp'.
2) Router A passes the route to RB with the same value, so it also shows in
'show ip bgp'in RB.
If you haven't changed the localpref value for the route (10.0.0.0) coming
from RC as you did, it would have had the default which is 100.
Rule: You will only see a value (100 or otherwise) next to local routes only
learned through IBGP.
Since Localpref value doesn't travel with the route outside the AS, you will
see this value empty next to routes learned through EBGP as you have in your
output.
HTH
Ya
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
GOLBERY Irhne
Sent: Wednesday, April 24, 2002 6:03 PM
To: ccielab@groupstudy.com
Subject: BGP and Local Preference
Hello,
I am looking for some URL or documentation "EXPLAINING IN DETAILS" how does
local preference is represented in the SHOW IP BGP command ?
10.0.0.0/8
------------------------------
| |
RC (AS 2) RD
| |
| |
| |
RA (AS 1) RB
I mean,
- RA(lo0:3.3.3.1) iBGP peer with RB (lo0:3.3.3.2) in AS 1
- RA(lo0:3.3.3.1) eBGP peer with RC (lo0:3.3.3.3) in AS 2
- RB(lo0:3.3.3.2) eBGP peer with RD(lo0:3.3.3.4) in AS 2
RA set a Local preference of 200 for network 10. 0.0.0 announced by RC
RB doesn 't change the defaul local preference
When looking at the sh ip bgp,
RB#sh ip bgp
Network Next Hop Metric LocPrf Weight
Path
* 10.0.0.0/8 3.3.3.4 0 2 i
*>i 3.3.3.1 200 0 2 i
RA#sh ip bgp
Network Next Hop Metric LocPrf
Weight Path
*> 10.0.0.0/8 3.3.3.3 200 0 2 i
How does the "show ip bgp command" interpret the information of the local
preference ?
I need to find details informations.
Thanks for your help
Irene.
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