From: Mahmud, Yasser (YMahmud@Solutions.UK.ATT.com)
Date: Mon Nov 25 2002 - 20:16:22 GMT-3
Brian,
For OSPF routes.
They will only synchronize when the OSPF router-id and bgp router-id match,
so can be fixed by making sure the router
generating the OSPF and BGP routes have the same router-id for both
protocols
The problem is that for the routes reflected by the RR , it changes the
router-id of bgp routes to itself.
However the router-id for the OSPF 'O' type routes still remains the router
which generated the routes so hence you get no match
b/w the router id of the IGP and the BGP route
Could you please clarify that this means it is not fixable unless the below
(as mentioned in your previous thread)??
1. fully mesh your iBGP sessions
2. use confederation
3. use another IGP besides OSPF
4. turn synchronization off
Just wondering for lab purposes if this crops up and asked to not create an
IBGP session b/w the route-reflector clients and not to turn off
synchronization and to redistribute the loopback routes via OSPF.
Then do I in addition reditsribute routes those via another IGP if I have
another routing protocol running on both the routers
(as it may not mention I can't redistribute via another routing protocol) &
if not possible what else can I do ???
Thks,
Yasser
-----Original Message-----
From: Brian McGahan [mailto:brian@cyscoexpert.com]
Sent: Monday, November 25, 2002 8:52 PM
To: 'Rich Doty'; ccielab@groupstudy.com
Subject: RE: BGP route-reflector client not installing IBGP routes
Rich,
Are you using OSPF as your IGP and have synchronization on? If
so, there is an extra condition that you must satisfy to meet the
synchronization rule.
"Paths marked as "not synchronized" in the show ip bgp <longer-prefixes>
output. If BGP synchronization is enabled, which it is by default in
Cisco IOSR Software, there must be a match for the prefix in the IP
routing table in order for an internal (iBGP) path to be considered a
valid path. If the matching route is learned from an OSPF neighbor, its
OSPF router ID must match the BGP router ID of the iBGP neighbor. Most
users prefer to disable synchronization using the no synchronization BGP
subcommand."
http://www.cisco.com/en/US/tech/tk648/tk365/technologies_tech_note09186a
0080094431.shtml
There are many threads that cover this issue, such as the following one:
http://www.groupstudy.com/archives/ccielab/200209/msg01765.html
HTH
Brian McGahan, CCIE #8593
Director of Design and Implementation
brian@cyscoexpert.com
CyscoExpert Corporation
Internetwork Consulting & Training
Voice: 847.674.3392
Fax: 847.674.2625
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Rich Doty
> Sent: Monday, November 25, 2002 2:11 PM
> To: ccielab@groupstudy.com
> Subject: BGP route-reflector client not installing IBGP routes
>
> I have a route reflector R5, and 2 route reflector clients R3, R6. I'm
> passing IBGP routes, and they are seen by R5/R3 in the BGP table. They
> are, however, not being seen as >, or reachable (and injected into the
> IP routing table). Both the destination prefix and next-hop are listed
> in the IGP routing entries, and the prefixes match. Does anyone have
any
> idea why these routes are not being installed?
>
> Thanks,
>
> Rich
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