From: Cezar Fistik (cfistik@moldovacc.md)
Date: Wed Feb 19 2003 - 13:39:09 GMT-3
Hi all,
The network is as follows:
AS200 -------- AS400
\ /
R1--R2--R3
R1, R2, R3 are all in AS500. R2 is a route reflector. AS400 receives a
route, let's say to 20.20.20.0/24 from anohter AS (not shown here). AS400
sends this route to AS500, exactly to R3 and to AS200. AS200 also sends
this route to SA500, to R1. No synch is configured on all routers in AS500
and next-hop-self is configuredon R1 and R3. All routers in AS500 know
about all nets in SA200 and AS400.
Here is the point where something that I cannot understand happens.
R3 sends the route to R2 (RR). R2 sends the route to R1 (RR Client).
R1 receives the route from AS200 and AFAIK it should send it to R2(its
route reflector), btu it doesn't. More strange is the fact that R2 and R3
prefer the path to 20.20.20.0/24 through AS400, but R1 prefers the path
through 200 400, despite R1 has info about both paths in its BGP table.
I was wondering, why R2 and R3 don't even have the route to 20.20.20.0/24
through AS200. They only have one route through AS400 drectly.
As I mentioned R1 doesn't send the route to 20.20.20.0/24 that it received
from AS200 to its internal neighbor, but I tried to shutdown the interface
between the R2 and R3 and the route to 20.20.20.0/24 immediately appears in
R2 table
If I change on R2 route selection attributes, making the 20.20.20.0/24 more
preferable through AS200 then all the routers in AS500 selects this route,
I mean tht R1 starts sending this route to R2.
In a word, I'm confused and if anybody knows what happens here please be so
kind and give me an advice.
Thanks,
Cezar Fistik
This archive was generated by hypermail 2.1.4 : Sat Mar 01 2003 - 11:06:31 GMT-3