From: Volkov, Dmitry (Toronto - BCE) (dmitry_volkov@xxxxxxxxx)
Date: Mon Aug 26 2002 - 18:23:48 GMT-3
Hello group,
Nobody answered yet !!!
Is this absolutely no real life case ???
Shortly again :) - When we redistr BGP into OSPF, OSPF creates LSA 5 flooded
anywhere (with except stubs)
These LSAs have ADV Router (in ospf DB) with RID of redistr router.
When Route reflector gets BGP route from redistr router - OSPF RID and BGP
RID of route learned via OSPF and via BGP are equal. So route is
"synchronized, best"
When BGP route is reflected from RR to internal peers - OSPF RID of
Originator of route is still the same ("from RID of redist router" - LSA 5
are not changed), but route learned via BGP shows "from RID of RR", despite
that Originator of route is still the same and because, I guess, OSPF RID
doesn't match BGP RID where route learned from - route "not synchronized"
http://www.cisco.com/warp/public/459/25.shtml
What to do ?? if Sync must be enabled and IBGP full mesh is not allowed.
Can we say that if Sync enabled with OSPF - IBGP has to be full meshed ???
R2 -is RR, R1 - redistr point from BGP to OSPF, R6 - RR client (R1, R2 and
R6 in the same AS)
route 160.100.100.0/24 - learned by R1 via EBGP:
r2#sh ip bgp 160.100.100.0
BGP routing table entry for 160.100.100.0/24, version 10
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Advertised to non peer-group peers:
133.7.4.4 133.7.6.6
2001, (Received from a RR-client)
133.7.1.1 (metric 75) from 133.7.1.1 (133.7.1.1) <-----------
DIFFERENCE !!!
Origin IGP, metric 0, localpref 100, valid, internal, synchronized,
best
r2#sh ip ro 160.100.100.0
Routing entry for 160.100.100.0/24
Known via "ospf 1", distance 110, metric 1
Tag 2, type extern 2, forward metric 74
Last update from 133.7.28.3 on Ethernet0/0, 02:28:36 ago
Routing Descriptor Blocks:
* 133.7.28.3, from 133.7.1.1, 02:28:36 ago, via Ethernet0/0
Route metric is 1, traffic share count is 1
====================================================================
r6#sh ip bgp 160.100.100.0
BGP routing table entry for 160.100.100.0/24, version 0
Paths: (1 available, no best path)
Not advertised to any peer
2001
133.7.1.1 (metric 75) from 133.7.2.2 (133.7.2.2) <-------------
DIFFERENCE !!!
Origin IGP, metric 0, localpref 100, valid, internal, not synchronized
Originator: 133.7.1.1, Cluster list: 133.7.2.2
r6#sh ip ro 160.100.100.0
Routing entry for 160.100.100.0/24
Known via "ospf 1", distance 110, metric 1
Tag 2, type extern 2, forward metric 74
Last update from 133.7.28.3 on Ethernet0, 02:29:31 ago
Routing Descriptor Blocks:
* 133.7.28.3, from 133.7.1.1, 02:29:31 ago, via Ethernet0
Route metric is 1, traffic share count is 1
Dmitry
-----Original Message-----
From: Volkov, Dmitry (Toronto - BCE) [mailto:dmitry_volkov@ca.ml.com]
Sent: Monday, August 26, 2002 11:14 AM
To: 'ccielab@groupstudy.com'
Subject: Again BGP sync/rid problem
Hello,
Well, now I'm also stacked with this Sysnc/RID problem.
I'm doing Solie's "Unnamed Lab". The requirement : Syncronize BGP with OSPF.
R1 (rid 133.7.1.1) runs BGP AS 2010 and peering with backbone router AS
2001.
R1 gets 4 EBGP routes from Backbone.
R1 runs IBGP with R2 (rid 133.7.2.2), R2 runs IBGP with R6 (rid 133.7.6.6).
There is OSPF between R1, R2, R6.
R2, R3 and R6 on common ethernet segment. R2 and R6 connected to R1 via R3
(which runs OSPF only, NO BGP)
R1----R3----R2
|
R6
So
1)I redistributed BGP to OSPF on R1 with next-hop-self , R2 is OK - all BGP
routes from Backbone are valid:
Network Next Hop Metric LocPrf Weight Path
*>i160.100.100.0/24 133.7.1.1 0 100 0 2001 i
*>i160.100.128.0/24 133.7.1.1 0 100 0 2001 i
*>i160.100.129.0/24 133.7.1.1 0 100 0 2001 i
*>i160.100.130.0/24 133.7.1.1 0 100 0 2001 i
r2#
2) made R2 as Route reflector.
R6 gets BGP routes from backbone via R2. But these routes are not
synchronized.
I guess this is because route 160.100.100.0/24 is learned via BGP from R2
(133.7.2.2),
but it's also known via IGP (OSPF) from R3 (133.7.28.3 - R3's IP on common
ethernet segment)
My question is : WHAT TO DO IN SUCH SITUATION. I don't see any workaround
without violating Lab requirements.
r6#sh ip ro 160.100.100.0
Routing entry for 160.100.100.0/24
Known via "ospf 1", distance 110, metric 1
Tag 2, type extern 2, forward metric 74
Last update from 133.7.28.3 on Ethernet0, 02:58:43 ago
Routing Descriptor Blocks:
* 133.7.28.3, from 133.7.1.1, 02:58:43 ago, via Ethernet0
Route metric is 1, traffic share count is 1
r6#sh ip bgp 160.100.100.0
BGP routing table entry for 160.100.100.0/24, version 0
Paths: (1 available, no best path)
Not advertised to any peer
2001
133.7.1.1 (metric 75) from 133.7.2.2 (133.7.2.2)
Origin IGP, metric 0, localpref 100, valid, internal, not synchronized
Originator: 133.7.1.1, Cluster list: 133.7.1.1
r6#
Thanks,
Dmitry
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:48:38 GMT-3