[183266] in North American Network Operators' Group
BGP advertise-best-external on RR
daemon@ATHENA.MIT.EDU (Mohamed Kamal)
Mon Aug 24 15:07:52 2015
X-Original-To: nanog@nanog.org
From: Mohamed Kamal <mkamal@noor.net>
To: NANOG <nanog@nanog.org>
Date: Mon, 24 Aug 2015 21:07:45 +0200
Errors-To: nanog-bounces@nanog.org
Hi,
I have a classic network design with 3 gateways, each receive a default
route from different upstream provider. Each gateway has a BGP session
with a route-reflector, which in turns reflects the best BGP route to
the other PE routers in the network. The route-reflectors are running
the SRE train (12.2(33)SRE1) and here exist the problem.
I need to leak all the default routes (3 default routes) from the
gateways into the PE routers. I have done this via bgp
advertise-best-external on the gateways. So far, the default routes
exist on the route-reflector, however it's suppressed as the RR will
only send the best path.
I have configured bgp advertise-best-external also on the RR but it
didn't work, because the RR didn't see that the different default routes
received are of "external" type. Cisco didn't state that clearly and it
only stated that bgp best external feature won't work on the RR unless
you get an ASR loaded with an IOS-XE 3.4 or later!
Anyhow, do anyone here has a suggestion of how to get this done without
replacing my RR sticking to this classical network design?
Thanks.
--
Mohamed Kamal
Core Network Sr. Engineer
