NANOG@Mar 23, 2009

Date: Mon, 23 Mar 2009 07:40:38 +0000
From: Andy Davidson
Subject: Re: AS path weirdness
To: Jason Lewis
Cc: NANOG list
Message-ID: <1CDE960B-63CD-4D42-8C42-1C6BC475C371@nosignal.org>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes


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


4バイトAS(32bitAS)について各所で既に説明されたことに関する質問と回答。
回答側も度重なるとだんだんスマートになってくる。