From: pppccie@gmail.com
Date: Wed Jun 29 2005 - 02:55:21 GMT-3
Hi KC,
from the BB2 sh ip bgp, it show the route from 10.1 has a metric
of 100 and 80.8 has a metric of 5. Lowest MED is preferred. Try revert the
MED value on your configuration, and it should work. Thanks.
Priscilla
----- Original Message -----
From: "k c" <jwongccie@yahoo.com.hk>
To: <ccielab@groupstudy.com>
Sent: Tuesday, June 28, 2005 9:24 PM
Subject: BGP MED problem
> Hi Group,
>
> BB1 (AS500) --- R1 (AS100)
> | |
> | R2 (AS200)
> | |
> BB2 (AS500) --- R8 (AS300)
>
> R1 and R8 announce 2.2.2.0/24 to BB1 & BB2. Without modifying any
attributes, BB1 will choose R1 and BB2 will choose R8 as next hop. The task
is to make sure BB2 will reach 2.2.2.0/24 via BB1. AS prepend method is not
allowed. When I use metric, it doesn't work? BB2 still choose R8. How can I
influence bb2 to choose R8? How many methods (beside AS prepend) can I use?
>
> bb2-7206g1>sh ip bgp
> BGP table version is 23, local router ID is 208.10.90.1
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
> r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
> Network Next Hop Metric LocPrf Weight Path
> *> 2.2.2.0/24 192.168.80.8 5 0 300 200 ?
> * i 192.168.10.1 0 100 0 100 200 ?
> *> 5.5.5.0/24 192.168.80.8 0 300 200 ?
> * i 192.168.10.1 0 100 0 100 200 ?
> bb2-7206g1>sh ip bgp 2.2.2.0
> BGP routing table entry for 2.2.2.0/24, version 23
> Paths: (2 available, best #1, table Default-IP-Routing-Table)
> Advertised to update-groups:
> 2
> 300 200
> 192.168.80.8 from 192.168.80.8 (136.10.8.8)
> Origin incomplete, metric 5, localpref 100, valid, external, best
> 100 200
> 192.168.10.1 (metric 5) from 12.12.12.1 (100.10.15.1)
> Origin incomplete, metric 0, localpref 100, valid, internal
> bb2-7206g1>
>
> 8. If the origin codes are the same, prefer the route with the lowest MED
metric attribute.
> 9. Prefer the external BGP (eBGP) path over the iBGP path.
>
> Thanks.
>
> &3'Y.I3q*>!A&,_'
>
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