ASPATH Loop

Ivan Pepelnjak ip at ioshints.info
Sun May 10 07:33:39 CDT 2009


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 at gmail.com] 
> Sent: Sunday, May 10, 2009 12:52 PM
> To: nanog at 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





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