[e2e] opening multiple TCP connections getting popular
lachlan.andrew at gmail.com
Fri Aug 31 08:29:12 PDT 2007
On 31/08/2007, Joe Touch <touch at isi.edu> wrote:
> 'fair' depends on an agreed concept of
> fairness. We have one now - per-TCP connection, relative to RTT. That's
> not perfect, but it is a definition, and it does work.
Per connection, relative to RTT, relative to packet size, relative to
number of points of congestion. Is it also "relative to corruption
rate" or is that not part of the definition?
Yes, it is agreed upon, but I'd venture to suggest that it is mainly
agreed upon by (a) those few who played a role in developing the
algorithm which implements it (at low BDP etc), and (b) those trying
to gain the support of those original designers.
Per-flow max-min is much more "agreed upon" in the research community
as an *objective*, as distinct from the outcome of a particular
algorithm (which was a very useful emergency bandaid). I haven't done
a survey, but I'm confident that if you asked the average user, they
would be more in favour of max-min fairness than TCP-friendly
You mentioned that the IETF's role isn't to do research. How about a
commitment to be *open* to research into a concept of fairness which
is more systematic and less historically-driven? The current
impression that I get from the research community is that the IETF
will on principle block any proposal which implements a "better"
form of fairness (i.e. one with a theoretical justification and more
in line with a layman's notion of fairness, such as user-pays). Bob's
experience seems to bear that out...
What exactly do you mean by a fairness definition "working"? The
internet still "works", who knows if that is just because of
"receiver window fairness" or "small P2P user-base fairness", or
"overprovisioning fairness" rather than "per flow fairness" :)
Lachlan Andrew Dept of Computer Science, Caltech
1200 E California Blvd, Mail Code 256-80, Pasadena CA 91125, USA
Phone: +1 (626) 395-8820 Fax: +1 (626) 568-3603
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