[tor-bugs] #15744 [Tor]: Is 16384 introductions a sane limit for IP rotation?

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#15744: Is 16384 introductions a sane limit for IP rotation?
-------------------------+--------------------------------
     Reporter:  dgoulet  |      Owner:
         Type:  defect   |     Status:  new
     Priority:  normal   |  Milestone:  Tor: 0.2.7.x-final
    Component:  Tor      |    Version:
   Resolution:           |   Keywords:  SponsorR, tor-hs
Actual Points:           |  Parent ID:  #15714
       Points:           |
-------------------------+--------------------------------

Comment (by karsten):

 Here are some logs containing daily relay heartbeats containing
 introduction circuit histograms from dgoulet:

 {{{
 May 06 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (230,
 30, 10, 0, 0, 0, 0, 0, 0)
 May 06 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (180, 60,
 10, 10, 0)
 May 07 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (220,
 20, 10, 10, 10, 0, 0, 0, 0)
 May 07 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (170, 40,
 20, 10, 10)
 May 08 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (260,
 50, 10, 10, 10, 0, 0, 10, 0)
 May 08 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (190, 60,
 20, 40, 20)
 May 09 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (260,
 40, 10, 10, 0, 0, 0, 0, 0)
 May 09 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (190, 60,
 20, 40, 10)
 May 10 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (260,
 40, 10, 10, 10, 10, 0, 0, 0)
 May 10 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (170, 50,
 30, 60, 30)
 May 11 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (270,
 30, 20, 10, 0, 10, 0, 0, 0)
 May 11 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (190, 60,
 20, 50, 10)
 May 12 08:33:31.000 [warn] Intro HS stats: Introductions histogram: (290,
 30, 10, 10, 0, 0, 0, 0, 0)
 May 12 08:33:31.000 [warn] Intro HS stats: Lifetimes histogram: (220, 60,
 20, 30, 10)
 }}}

 I'm attaching
 [https://trac.torproject.org/projects/tor/attachment/ticket/15744
 /introduction-circuits-2015-05-19.pdf two graphs] based on these logs:

  - The first graph shows the distribution of introductions received per
 introduction circuit.  Over 80% of introduction circuits don't receive a
 single introduction, and less than 5% of introduction circuits see a few
 hundred or a few thousand introductions.

  - The second graph shows the distribution of introduction circuit
 lifetimes.  More than half of all introduction circuits are closed within
 the first 30 minutes.  But once an introduction circuit exceeds that
 lifetime it's quite common for it to become 5, 18, or even 25 hours old.
 For some reason roughly 5% of introduction circuits get older than 25
 hours, where their exact lifetime cannot be extracted from the logs.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/15744#comment:12>
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