From: Filyurin, Yan (yan.filyurin@eds.com)
Date: Thu Apr 12 2007 - 15:04:01 ART
Hi group, I have the following scenario involving private AS and this is
a little bit of real world requirement, but could help in studying.
I have three routers and two core networks. Core networks 1 connects to
R1 originates routes from one private AS X and peers to R2 in another
private AS Y and R2 also originates a couple of routes and R2 peers to
R3 in another private AS Z. R3 also peers to a core network of various
private ASs
My goal is to be able to receive routes from R1, on R2, filter them
based on certain AS path, then pass them over to R3 and at the same time
be able to strip all the private ASs from core network one and just make
core network 2 (connected to R3) think that all the R3 routes have Z Y X
in their AS and routes that R2 originates have Z Y in their path.
So I want to add remove private-as statement on R2 to R3 and set up an
outgoing route map that will also AS prepend and I know it will work,
but my question is will it work if I try to match in that route map on
AS path attributes from R3.
I have as-path list 10 that is used by R2 to match routes that it can
receive from R3. Could I do the following on R2
neighbor 3.3.3.3 remote-as 655293
neighbor 3.3.3.3 description eBGP peer to R3
neighbor 3.3.3.3 route-map R2toR3 out
neighbor 3.3.3.3 remove-private-as
ip as-path access-list 10 permit ^X_W$ (as I want to receive only those
that match AS X and W)
and do that:
route-map R2roR3 permit 10
match as-path 10
set as-path prepend X
route-map R2roR3 permit 20
And so that routes that come from R1 will have path X prepended and
those that originate on R2 won't. I plan to try it in the lab, but
wanted to ask first.
Thank you
This archive was generated by hypermail 2.1.4 : Tue May 01 2007 - 08:28:35 ART