[139028] in North American Network Operators' Group
Re: Question about AS Origin changes
daemon@ATHENA.MIT.EDU (Florian Weimer)
Fri Mar 25 09:53:22 2011
To: "Yaoqing\(Joey\) Liu" <joey.liuyq@gmail.com>
From: Florian Weimer <fweimer@bfk.de>
Date: Fri, 25 Mar 2011 13:53:16 +0000
In-Reply-To: <AANLkTimo=rqNaktv-u8ju+xOmEd7yAFgStNOB7N9oofb@mail.gmail.com>
(Yaoqing Liu's message of "Thu\, 24 Mar 2011 22\:24\:53 -0500")
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
* Yaoqing Liu:
> I am wondering if anyone can give me possible reasons for some uncommon B=
GP
> 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 bac=
k.
> In many instances the prefix simply switches back and forth for hours or
> even days and sometimes very rapidly . Below I=E2=80=99m including an ex=
ample 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).
--=20
Florian Weimer <fweimer@bfk.de>
BFK edv-consulting GmbH http://www.bfk.de/
Kriegsstra=C3=9Fe 100 tel: +49-721-96201-1
D-76133 Karlsruhe fax: +49-721-96201-99
