Hi NANOG list, I am wondering if anyone can give me possible reasons for some uncommon BGP origin change activity. What we see is that sometimes the origin for a prefix seems to change from a customer AS to it upstream provider and back. In many instances the prefix simply switches back and forth for hours or even days and sometimes very rapidly . Below I’m including an example of some of the activities I see. Prefix 202.83.96/20 on border router 154.11.98.225(AS 852) At 14:10:56 Dec 04 2010, the BGP path with AS18106 as the origin At 14:11:57, the BGP path with AS9255 as the origin At 14:14:27, the BGP path with AS18106 as the origin. Thanks, Yaoqing
* Yaoqing Liu:
I am wondering if anyone can give me possible reasons for some uncommon BGP origin change activity. What we see is that sometimes the origin for a prefix seems to change from a customer AS to it upstream provider and back. In many instances the prefix simply switches back and forth for hours or even days and sometimes very rapidly . Below I’m including an example of some of the activities I see.
This is expected if the upstream has a static route for the prefix (or a route which redistributed from another routing protocol). This could be a leftover from a non-BGP setup with the customer. Or this could be some sort of backup procedure (perhaps prompted by the instability of the BGP link). -- Florian Weimer <fweimer@bfk.de> BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99
participants (2)
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Florian Weimer -
Yaoqing(Joey) Liu