From: Victor Cappuccio (cvictor@protokolgroup.com)
Date: Mon May 15 2006 - 00:17:40 ART
Hi Brain, many thanks for your contribution to this list as always
Answering your question:
If you have the same Router ID this happens:
*May 14 20:55:21.632: %OSPF-4-DUP_RTRID_NBR: OSPF detected duplicate
router-id 10.2.2.2 from 204.12.1.2 on interface FastEth0
But I got interested in one point you mentioned, I love SRT...
"R3 into accepting the route if you set R2's OSPF RID to be the same as R1's
BGP RID."
please what I'm doing wrong?
Having this situation
10.1.1.0
|
(R2)
|
BGP
|
(R1)---BGP---(R3)
So I did that:
R2#show ip ospf
Routing Process "ospf 1" with ID 10.2.2.2
R1#show run | be router bgp
router bgp 100
synchronization
bgp router-id 10.2.2.2
R1#show ip bgp summ
BGP router identifier 10.2.2.2, local AS number 100
BGP table version is 1, main routing table version 1
42 network entries using 4914 bytes of memory
42 path entries using 2184 bytes of memory
7/0 BGP path/bestpath attribute entries using 868 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
1 BGP community entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 8038 total bytes of memory
BGP activity 176/134 prefixes, 296/254 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
10.1.1.1 4 100 4564 2308 1 0 0 00:13:39 2
10.6.6.6 4 100 83 66 1 0 0 00:24:46 40
BUT:
R3#show ip bgp
BGP table version is 101, local router ID is 10.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - in
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.0.0.0 0.0.0.0 0 32768 i
*> 163.1.0.0 0.0.0.0 0 32768 ?
R3#
What I'm doing wrong here :S
R1#show run | be router bgp 100
router bgp 100
synchronization
bgp router-id 10.2.2.2
bgp log-neighbor-changes
neighbor 10.1.1.1 remote-as 100
neighbor 10.1.1.1 update-source Loopback0
neighbor 10.1.1.1 route-reflector-client
neighbor 10.1.1.1 next-hop-self
neighbor 10.1.1.1 send-community
neighbor 10.6.6.6 remote-as 100
neighbor 10.6.6.6 update-source Loopback0
neighbor 10.6.6.6 route-reflector-client
neighbor 10.6.6.6 next-hop-self
neighbor 10.6.6.6 send-community
no auto-summary
Thanks
Victor.
-----Mensaje original-----
De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de Brian
McGahan
Enviado el: Domingo, 14 de Mayo de 2006 10:06 p.m.
Para: CCIEin2006
CC: ccielab@groupstudy.com
Asunto: RE: BGP Synchronization - When do OSPF and BGP router ID need to
match?
The OSPF RID needs to be unique. Try it out for yourself and see what
happens.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com <http://www.internetworkexpert.com/>
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
<http://forum.internetworkexpert.com/>
Live Chat: http://www.internetworkexpert.com/chat/
________________________________
From: CCIEin2006 [mailto:ciscocciein2006@gmail.com]
Sent: Sunday, May 14, 2006 9:09 AM
To: Brian McGahan
Cc: ccielab@groupstudy.com
Subject: Re: BGP Synchronization - When do OSPF and BGP router ID need
to match?
Excellent - this was just the answer I was looking for.
Thanks Brian.
As far as setting R2's OSPF RID to be the same as R1's BGP RID, would R1
and R2 even establish adjacency if they had the same OSPF RID?
On 5/14/06, Brian McGahan <bmcgahan@internetworkexpert.com> wrote:
The answer is... it depends. The synchronization rules states that for
every iBGP learned route you must have a matching IGP route, and if that
IGP is OSPF the BGP RID and the OSPF RID must match. Suppose that R1's
RID for both BGP and OSPF is 1.1.1.1 and R2's is 2.2.2.2. In that
circumstance the OSPF RID R3 sees will be 2.2.2.2 (the originator of the
LSA) and the BGP RID it sees will be 1.1.1.1 (the reflector of the BGP
route). In this case the route will not be considered for bestpath
selection. In this case you can trick R3 into accepting the route if
you set R2's OSPF RID to be the same as R1's BGP RID. The easier
solutions however would be to disable synchronization on R1 and R3, to
peer R2 and R3 via iBGP, or to run confederation inside the AS
(synchronization only applies to iBGP learned routes).
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
________________________________
From: nobody@groupstudy.com on behalf of CCIEin2006
Sent: Sat 5/13/2006 1:43 PM
To: ccielab@groupstudy.com
Subject: BGP Synchronization - When do OSPF and BGP router ID need to
match?
Hello group,
Please examine the following setup:
10.1.1.0
|
(R2)
|
BGP
|
(R1)---BGP---(R3)
All three routers are running ospf and iBGP with Synchronization
enabled.
R1 is acting as route reflector for R2 and R3.
Will the 10.1.1.0 network advertised by R2 appear in the BGP table of
R3?
If not please explain why.
This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:21 ART