[tor-bugs] #3443 [Tor Client]: Client with low CBT can't switch to a bridge if it's slow

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#3443: Client with low CBT can't switch to a bridge if it's slow
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 Reporter:  arma        |          Owner:                    
     Type:  defect      |         Status:  new               
 Priority:  major       |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client  |        Version:                    
 Keywords:  regression  |         Parent:                    
   Points:              |   Actualpoints:                    
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Changes (by mikeperry):

 * cc: mikeperry (added)


Comment:

 See path-spec.txt.

 The consensus params that govern this are cbtmaxtimeouts and
 cbtrecentcount. If cbtmaxtimeouts timeouts happen within the past
 cbtrecentcount circuits, we give up on CBT.

 Right now, the values are 18 and 20 respectively, based on statistical
 analysis of CBT data and the frequency of reset under normal conditions.
 It takes a while to build 20 circuits, but if that number is lower, we
 tend to end up giving up on CBT when we shouldn't, based on statistics.

 But, I didn't prove any of this, I just ran a bunch of test data and
 picked values that ended up not resetting too often. If 18/20 is too much,
 we can try lowering them.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/3443#comment:4>
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