[tor-relays] About relay size

[Scott Bennett]

Roman Mamedov <rm at romanrm.net> wrote:

> On Tue, 3 Oct 2017 09:53:46 -0400
> teor <teor2345 at gmail.com> wrote:
>
> > >     For interposing dual-protocoled nodes along the way, how many do there
> > > have to be for it to become "not too limiting"?
> > 
> > This is one of the questions we need researchers to answer.
>
> I can't help but feel you are overcomplicating this.
>
> Clients create a circuit by randomly picking 3 nodes out of the all-nodes
> pile, right? If all 3 happen to be IPv6-capable, then the circuit can go over
> IPv6 and all is fine. If some of the 3 happen to be IPv6-only while others are
> IPv4-only, the whole selection can be thrown away and repeated.
>
> That way IPv6-only relays could get some usage on a totally random basis, with
> no compromises and no restraining "of the next hop based on the previous one",
> not hurting anonymity. Clients just need to know which nodes are IPv4-only,
> IPv6-only or dual-stack, to not attempt unworkable combinations, discarding
> them instead.

     Looks good to me, Roman.  I like it better than what I suggested, though
adding some variability to path length had some appeal, too.  Your way is
certainly simpler.
     If tor ever starts to support TCP over UDP and/or TCP over SCTP, that
will be a similar situation for a while, where some relays can do both and
others are limited to one protocol or the other.
>
> And as there are more and more dual-stack or IPv6-only relays, the "throw
> away" step will be needed less and less often.
>
     Yet the same process could be applied to the TCP-over-non-TCP situation
quite easily, too.  I think I like your way even better now.
     My memory is a bit hazy on this, but I seem to recall watching a video
file of Roger Dingledine giving a talk somewhere about tor long ago in which
he commented happily that the tor network had grown to where it usually had
at least 300 nodes up and running at all times of day.  If 300 were enough
for path selection before, aren't they still enough?  Aren't there at least
300 IPv6-only nodes and at least 300 dual-protocol nodes now?  And, of
course, there must have been a time when the network was smaller than 300...


                                  Scott Bennett, Comm. ASMELG, CFIAG
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