[116839] in North American Network Operators' Group
Redundancy & Summarization
daemon@ATHENA.MIT.EDU (Gaynor, Jonathan)
Fri Aug 21 11:59:33 2009
Date: Fri, 21 Aug 2009 11:57:49 -0400
From: "Gaynor, Jonathan" <Jonathan.Gaynor@fccc.edu>
To: <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
My institution has a single /16 spread across 2 sites: the lower /17 is
used at site A, the upper /17 at site B. Sites A & B are connected
internally. Currently both sites have their own ISPs and only advertise
their own /17's. For redundancy we proposed that each site advertise
both their own /17 and the whole /16, so that an ISP failure at either
site would trigger traffic from both /17s to reconverge towards the
unaffected location.
My worry/question: will carriers down the line auto-summarize my
advertisements into a single /16, resulting in a 'load sharing' while
both sites are active? If you're a backbone carrier and you saw x.x/16
and x.x/17 (or x.x/16 and x.x.128/17) being advertised from the same
peer would you drop the longer match?
Regards and thanks,
Jon Gaynor, Senior Network Engineer
Fox Chase Cancer Center
(215) 214-4267, jonathan.gaynor@fccc.edu
