From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Sun May 14 2006 - 02:04:37 ART
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
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________________________________
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