[114392] in North American Network Operators' Group
RE: ASPATH Loop
daemon@ATHENA.MIT.EDU (Ivan Pepelnjak)
Sun May 10 12:28:18 2009
From: "Ivan Pepelnjak" <ip@ioshints.info>
To: "'yangyang. wang'" <wyystar@gmail.com>,
<nanog@nanog.org>
Date: Sun, 10 May 2009 14:33:39 +0200
In-Reply-To: <10fbbf5a0905100351p1663830aq78b2f82f836ad54c@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Multiple discontiguous copies of an AS number in the AS-path can also be
caused by the "original" Cisco IOS "local-as" feature, but in that case the
AS number in the middle would be fixed.
http://bit.ly/7TnCi
And there's always the AS-path prepending. Cisco IOS allows you to insert
anything in the AS path.
Ivan
http://www.ioshints.info/about
http://blog.ioshints.info/
> -----Original Message-----
> From: yangyang. wang [mailto:wyystar@gmail.com]
> Sent: Sunday, May 10, 2009 12:52 PM
> To: nanog@nanog.org
> Subject: ASPATH Loop
>
> Hi， NANOG：
>
> When I was analyzing the BGP RIB data from RouteViews,
> I found that there were aspath loop in many bgp rib entries.
> For example, in the file rib.wide.20090301.0319, the peer
> 202.249.2.169 in AS2497 observed the following aspaths:
>
> 3130 29283 3130 2914 2497
> 3130 7337 3130 2914 2497
