[183268] in North American Network Operators' Group
Re: BGP advertise-best-external on RR
daemon@ATHENA.MIT.EDU (Diptanshu Singh)
Mon Aug 24 15:59:35 2015
X-Original-To: nanog@nanog.org
From: Diptanshu Singh <diptanshu.singh@gmail.com>
In-Reply-To: <55DB6B81.60908@noor.net>
Date: Mon, 24 Aug 2015 14:16:41 -0500
To: Mohamed Kamal <mkamal@noor.net>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
BGP Add-Path might be your friend . You can look at diverse-path as well .
Sent from my iPhone
> On Aug 24, 2015, at 2:07 PM, Mohamed Kamal <mkamal@noor.net> wrote:
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> Hi,
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> I have a classic network design with 3 gateways, each receive a default ro=
ute from different upstream provider. Each gateway has a BGP session with a r=
oute-reflector, which in turns reflects the best BGP route to the other PE r=
outers in the network. The route-reflectors are running the SRE train (12.2(=
33)SRE1) and here exist the problem.
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> 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 th=
e gateways. So far, the default routes exist on the route-reflector, however=
it's suppressed as the RR will only send the best path.
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> 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 a=
re of "external" type. Cisco didn't state that clearly and it only stated th=
at bgp best external feature won't work on the RR unless you get an ASR load=
ed with an IOS-XE 3.4 or later!
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> Anyhow, do anyone here has a suggestion of how to get this done without re=
placing my RR sticking to this classical network design?
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> Thanks.
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> --=20
> Mohamed Kamal
> Core Network Sr. Engineer
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