[112862] in North American Network Operators' Group
Re: AS path weirdness
daemon@ATHENA.MIT.EDU (Andy Davidson)
Mon Mar 23 03:40:54 2009
From: Andy Davidson <andy@nosignal.org>
To: Jason Lewis <jlewis@packetnexus.com>
In-Reply-To: <49C4558C.8050306@packetnexus.com>
Date: Mon, 23 Mar 2009 07:40:38 +0000
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On 21 Mar 2009, at 02:48, Jason Lewis wrote:
> I'm not entirely sure what I'm looking at. The reserved AS, 65490
> appears in parentheses and I've never seen that in MRT formatted
> data and not sure why it's happening.
This has been observed when a vendor runs 32-bit AS aware code on part
of their edge, and non-32-bit AS aware code on a different part of
their edge.
> I'm also not clear on why I see 23456 *and* a 32 bit AS in the
> path. Is anyone else seeing this or is it something wacky at RRC04?
> 91.207.218.0/23|29222 6830 (65490) 3356 35320 3.21 23456
There's some history with this prefix.
http://www.andyd.net/media/talks/asn4_breaks_network.pdf [from nanog45]
Andy
