[tor-bugs] #8240 [Tor]: Raise our guard rotation period

[Tor Bug Tracker & Wiki]

#8240: Raise our guard rotation period
----------------------------------------------------+-----------------------
 Reporter:  arma                                    |          Owner:                    
     Type:  defect                                  |         Status:  needs_review      
 Priority:  major                                   |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor                                     |        Version:                    
 Keywords:  tor-client needs-proposal 023-backport  |         Parent:                    
   Points:                                          |   Actualpoints:                    
----------------------------------------------------+-----------------------

Comment(by mikeperry):

 These are hard questions. People already hate the fact that when their
 relays get the guard flag: throughput drops off for days. I don't believe
 the transition takes weeks though (probably thanks to the bw auths), but I
 have not studied it in detail.

 One way to improve this balancing problem might to adjust the Wxx weights
 such that the guard ones are dependent on how long you've had the guard
 flag vs this rotation parameter. If we had a curve to model the migration
 rate and metadata to record the Guard flag age to create points on this
 curve, this might not be too hard to do. I suppose a uniform migration
 rate might be as good an assumption as any...

 However, personally, I think that in reality clients are rotating off of
 their guards much quicker than even the 1.5mo limit. At least, it feels
 like my Tor clients were doing that when watching path bias counts.. I
 think this might be the same problem you describe when talking about the
 age of the median byte of the Guard flag (Guards may actually already
 going up and down/losing their flags way faster than our limits). For this
 reason, I'm wondering if simply changing the rotation period to 9.5mos
 might not actually change the rotation rate in practice.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8240#comment:6>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online