[88781] in North American Network Operators' Group
Re: Disaster recovery using as-prepend?
daemon@ATHENA.MIT.EDU (Todd Vierling)
Fri Feb 17 15:56:31 2006
Date: Fri, 17 Feb 2006 15:55:47 -0500 (Eastern Standard Time)
From: Todd Vierling <tv@duh.org>
To: Warren Kumari <warren@kumari.net>
Cc: "Christopher J. Pilkington" <christopher.j.pilkington@gmail.com>,
nanog@merit.edu
In-Reply-To: <4A43CB96-5C21-46C8-BC07-8250FF020F56@kumari.net>
Errors-To: owner-nanog@merit.edu
On Thu, 16 Feb 2006, Warren Kumari wrote:
> If your primary is connected to ISP_A and the backup is connected to ISP_B,
> customers connected to ISP_B MAY still flow to your backup DC (ISP_B will
> probably set local preference on all customer routes - you should be able to
> override this behavior with communities but not all providers support this (or
> honor it 100% of the time!))
And in addition to that, even multihomed customers of ISP_B may choose the
prepended route for a number of different reasons; for instance, ISP_B might
be a cheaper pipe for them, or there may be a smart-ish routing device or
scheme in play that overrides normal BGP decision making.
--
-- Todd Vierling <tv@duh.org> <tv@pobox.com> <todd@vierling.name>
