[81424] in North American Network Operators' Group
Re: Active BGP Probing and large AS-sets
daemon@ATHENA.MIT.EDU (Lorenzo Colitti)
Thu Jun 9 11:12:47 2005
Date: Thu, 09 Jun 2005 17:12:35 +0200
From: Lorenzo Colitti <lorenzo@ripe.net>
To: Randy Bush <randy@psg.com>
Cc: nanog@merit.edu, routing-wg@ripe.net,
Henk Uijterwaal <henk@ripe.net>,
Giuseppe Di Battista <gdb@dia.uniroma3.it>,
Maurizio Pizzonia <pizzonia@dia.uniroma3.it>,
Maurizio Patrignani <patrigna@dia.uniroma3.it>,
Massimo Rimondini <rimondin@dia.uniroma3.it>
In-Reply-To: <17064.22294.767322.958708@roam.psg.com>
Errors-To: owner-nanog@merit.edu
Randy Bush wrote:
>>Thus, to stop its announcement from being propagated by ASes 1, 2, and
>>3, an AS (say AS12654) might announce one of its prefixes with an
>>AS-path of 12654 {1,2,3}.
>
> won't that prevent 12654's announcements from being received by, as
> opposed to propagated by, 1, 2, and 3?
More or less. Technically, unless sender-side loop detection is used,
the routers in 1,2 and 3 will receive the announcement, but discard it
because it contains the local AS. However, the path will not be one of
the candidates for route selection, so it will probably not appear in
the output of a query for the prefix, which amounts to much the same.
Regards,
Lorenzo
--
lorenzo@ripe.net colitti@dia.uniroma3.it
www.ripe.net www.dia.uniroma3.it/~compunet
RIPE NCC Roma Tre Computer Networks research group
