From: DougAtHome (dcalton@fuse.net)
Date: Thu Apr 24 2003 - 16:08:00 GMT-3
Time is getting short for me. I have tried in a couple of lab scenarios,
including Solie's "Unnamed" lab, to implement Route Reflectors with
Synchronization turned on, where OSPF is the IGP. In both scenarios, a BGP RR
Client will not select IBGP routes as "best" because it will not synchronize.
Ultimately, this is due to the fact that Cisco mandates that the BGP and OSPF
source Router IDs match. Normally, this would not be a problem, but
apparently, IF the Route Reflector is NOT the redistribution router, route
reflection overwrites the BGP Router ID for the reflected routes with its own
Router ID. Here's a diagram of the situation:
R4
|
|
R1 -------R2 ---------R3
R2 in my diagram has an EBGP session with router R4, and IBGP session with R3.
R3 is a Route Reflector, listing both R2 and R1 as clients. BGP is
redistributed into OSPF at R2, of course, since this is where the external
routes are introduced. R3 synchronizes fine, but R1 shows all BGP routes as
unsynchronized.
I have tried various things, including Cluster IDs (couldn't make that config
"stick") and NOT making R1 a client, but still the same result - R3 replaces
the original Router ID source with its own Router ID, causing R1 to reject the
IGP route with the OSPF Router ID as a non match.
I have searched the archives of this and other news groups and found no
solution. The closest I came was a long discourse that ended with using
Confederations.
I guess I have two questions here:
1. What am I not doing that might make this thing work?
2. Why is Cisco so fussy about matching OSPF and BGP router ids anyway? This
seems to contradict the behavior of Route Reflection, and makes
Synchronization not only out of date, but non-functional to boot.
Yeah, I know nobody uses Synchronization these days, but I'm studying for the
lab (Sunday's the day for me =o... )
This archive was generated by hypermail 2.1.4 : Thu May 01 2003 - 13:36:05 GMT-3