From: OhioHondo (ohiohondo@columbus.rr.com)
Date: Fri May 09 2003 - 21:22:54 GMT-3
The Best Route selection does not use admin distance as a selection
criteria. Whatever is selected as Best Path get put in the IP routing table.
If it is an EBGP route, the admin will be 20. If it is an IBGP route, the
admin will be 200.
I use authentication between by EBGP peers and on one of my routers I
noticed that the IBGP route became the Beat Path on one of my routers even
though the EBGP route should have been selected. After the EBGP connection
came up, the IBGP route remained the Bset Path. Note that The EBGP
connection, due to the authentication, was slow in coming up (2524-1 with
12.1 IOS).
The BGP decision process did not re-evaluate until I took the IBGP route
down. Then the EBGP route became the Best Route and remained the Best Route
even after the IBGP route became available again. I thought this was some
type of anomaly (bug).
Any comments???? {=@)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Richard Davidson
Sent: Friday, May 09, 2003 4:30 PM
To: groupstudy
Subject: confederation path selection and Admin distance?
confederation path selection and Admin distance?
I have a confederation issue. I can't figure out why
my router is selecting the iBGP confederation peer as
apposed to my eBGP peer.
My router has to paths. I think, before the path
selection algorithm the router looks at admin
distance. Well the route that is being injected has a
distance of 200 and the route that is not has a
distance of 20. I brought down the link to the iBGP
confederation peer and the eBGP neighbor with a
distance of 20 came up.
See attached:
router bgp 65001
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 100
bgp confederation peers 65000
neighbor 172.16.101.1 remote-as 65001
neighbor 172.16.101.1 update-source Loopback0
neighbor 172.16.103.1 remote-as 65000
neighbor 172.16.103.1 ebgp-multihop 255
neighbor 172.16.103.1 update-source Loopback0
neighbor 172.30.4.10 remote-as 1771
r4#sib 140.10.1.0
BGP routing table entry for 140.10.1.0/24, version 99
Paths: (2 available, best #1, table Default-IP-Routing-Table)
Advertised to non peer-group peers:
172.16.101.1 172.30.4.10
(65000) 1581 1776
172.40.10.10 (metric 200) from 172.16.103.1 (172.16.103.1)
Origin IGP, localpref 100, valid, confed-external, best
1771 1581 1776
172.30.4.10 from 172.30.4.10 (192.88.1.1)
Origin IGP, localpref 100, valid, external
r4#i | i 140.10.1.0
B 140.10.1.0 [200/0] via 172.40.10.10, 00:27:50
This archive was generated by hypermail 2.1.4 : Mon Jun 02 2003 - 15:13:40 GMT-3