[98714] in North American Network Operators' Group
Re: Extreme congestion (was Re: inter-domain link recovery)
daemon@ATHENA.MIT.EDU (Fred Baker)
Thu Aug 16 03:04:16 2007
In-Reply-To: <20070816051324.GJ23762@skywalker.creative.net.au>
Cc: nanog <nanog@merit.edu>
From: Fred Baker <fred@cisco.com>
Date: Wed, 15 Aug 2007 23:46:12 -0700
To: Adrian Chadd <adrian@creative.net.au>
Errors-To: owner-nanog@merit.edu
On Aug 15, 2007, at 10:13 PM, Adrian Chadd wrote:
> Well, emprically (on multi-megabit customer-facing links) it takes
> effect immediately and results in congestion being "avoided" (for
> values of avoided.) You don't hit a "hm, this is fine" and "hm,
> this is congested"; you actually notice a much smoother performance
> degredation right up to 95% constant link use.
yes, theory says the same thing. It's really convenient when theory
and practice happen to agree :-)
There is also a pretty good paper by Sue Moon et al in INFOCOMM 2004
that looks at the Sprint network (they had special access) and looks
at variation in delay pop-2-pop at a microsecond granularity and
finds some fairly interesting behavior long before that.
