From: ccie2be (ccie2be@nyc.rr.com)
Date: Thu Feb 24 2005 - 14:43:29 GMT-3
Hi guys,
I've come across something I've never seen before in a bgp table.
Here's the config:
router bgp 300
no synchronization
bgp router-id 150.1.3.3
bgp log-neighbor-changes
neighbor 142.1.34.4 remote-as 300
neighbor 204.12.1.6 remote-as 100
neighbor 204.12.1.254 remote-as 54
neighbor 204.12.1.254 local-as 100
neighbor 204.12.1.254 route-map FROM-BB3 in
route-map FROM-BB3 permit 10
set as-path prepend 54 54 54
Here's the topology:
R3 <-----> R4 (AS 300)
| /
|----------------| /
| | /
BB3 R 6 <---------> BB1 (AS 54)
^ ^
AS54 AS100
r3(config-route-map)#do sh ip bgp
BGP table version is 14, local router ID is 150.1.3.3
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
* 28.119.16.0/24 204.12.1.254 0 0
54 54 54 100 54 i
* i 142.1.46.6 0 100 0
100 54 i
*> 204.12.1.254 0
100 54 i
* 28.119.17.0/24 204.12.1.254 0 0 54
54 54 100 54 i
* i 142.1.46.6 0 100 0
100 54 i
*> 204.12.1.254 0
100 54 i
* 112.0.0.0 204.12.1.254 0
54 54 54 100 54 50 60 i
* i 142.1.46.6 0 100 0
100 54 50 60 i
*> 204.12.1.254 0
100 54 50 60 i
* 113.0.0.0 204.12.1.254 0
54 54 54 100 54 50 60 i
* i 142.1.46.6 0 100 0
100 54 50 60 i
*> 204.12.1.254 0
100 54 50 60 i
(Sorry if the formatting doesn't come out properly.)
Notice that each of the routes has 2 paths which both show 204.12.1.254 as
the next hop.
This is misleading since the 2nd 204.12.1.254 entry is really from
204.12.1.6
Is there any way I can configure R3 such that the prefixes learned from
204.12.1.6
show the next-hop as 204.12.1.6 instead of automatically changing it to
204.12.1.254?
I know that I can add on R6 the next-hop-self command pointing to R3 to
change this but can the same effect
be achieved by ONLY changing the config on R3?
My objective is to have the BGP process on R3 and R4 prefer the path via
142.1.46.6 by using prepend.
TIA, Tim
This archive was generated by hypermail 2.1.4 : Thu Mar 03 2005 - 08:51:25 GMT-3