ASPATH Loop

Sun May 10 10:59:31 UTC 2009

On 10/05/2009, at 10:51 PM, yangyang. wang wrote:

> As we know, BGP instance running on routers don't allow loop in
> ASPATH, why they can be seen in RIBs? It's some particular technical
> configuration in practice? OR What's wrong with AS3130??

Look at the WHOIS entry for AS3130, and notice in the comments field:
http://psg.com/as3130/

"Regarding strange announcements by AS 3130 of prefixes in  
98.128.0.0/16" is in the big headings on the top of that page.

He is no doubt announcing it with an origin AS of 3130 so no person or  
router complains about inconsistent origins.

--
Nathan Ward