[tor-dev] Fairness between circuits

Nick Mathewson nickm at freehaven.net
Thu May 12 02:59:37 UTC 2011

2011/5/6 Björn Scheuermann <scheuermann at informatik.uni-wuerzburg.de>:
> We implemented Tor's scheduling mechanisms, the N23 extension, and our
> fairness mechanism in an event-based network simulator (ns-3).
> Independent from the question of inter-circuit fairness, we were able to
> confirm the key findings in the DefenestraTor tech report with respect
> to N23 based on this independent implementation. Moreover, we found that
> N23 does not solve the fundamental fairness problems - but N23 in
> combination with our fairness mechanism does an excellent job in this
> regard.
> We explain all this in much more detail in a paper:
>  F. Tschorsch, B. Scheuermann: Tor is Unfair - and What to Do About It
>  http://robotik.informatik.uni-wuerzburg.de/tr481.pdf
> We're hoping for feedback and vivid discussions - we would be really
> interested in bringing these mechanisms into Tor.

Hi!  Let me kick the discussion off by asking how your work relates
(if at all!) to:

  1) This other work on using N23 with Tor ("DefenstraTor: Throwing
out Windows in Tor" by AlSabah, Bauer, Goldberg, Grunwald, McCoy,
Savage, and Voelker):
      (IMO it's a promising sign that two groups seem to be
independently converging on the same basic algorithm family.)

  2) The priority-queue-based circuit scheduling code originally
merged in Tor (starting with commit d3be00e0f).

  3) Your other scheduling/bandwidth allocation work (ticket 2536)

I'd also be interested in hearing what the DefenestraTor authors think
about above-linked paper and
the topic in general.


More information about the tor-dev mailing list