[tor-bugs] #6401 [Analysis]: Update Tor network models from CSET paper

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#6401: Update Tor network models from CSET paper
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 Reporter:  robgjansen                              |          Owner:  robgjansen
     Type:  task                                    |         Status:  new       
 Priority:  normal                                  |      Milestone:            
Component:  Analysis                                |        Version:            
 Keywords:  simulation, performance, network model  |         Parent:            
   Points:                                          |   Actualpoints:            
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Comment(by robgjansen):

 '''__The second stab__'''

 We used the Tor network model as described above, but changed it by
 reducing the web clients from 2301 down to 1500, and increasing the P2P
 clients from 9 to 50.

 '''Load on the network''' was distributed as follows:

 {{{
 TYPE    #XFERS  GiB     %
 im      20320   0.019   0.063
 web     63464   19.368  63.073
 bulk    1021    4.985   16.235
 p2p     374430  5.713   18.606
 perf50k 1023    0.049   0.159
 perf1m  586     0.572   1.864
 TOTAL   460844  30.707  100.000
 }}}
 '''Client performance''' is shown in
 [https://trac.torproject.org/projects/tor/attachment/ticket/6401/20120729-ec2
 -torperf-combined.pdf the attached graph here].

 The overall load was reduced by about 4 GiB, and the load distribution
 looks better (closer to ~40% bulk). I expected shadow client performance
 to be a bit faster, i.e. those dashed lines to move a little farther to
 the left than they did.

 I noticed the gap between TorPerf and Shadow seems to expand with the
 download length. Intuition tells me that either Shadow is miscalculating
 packet delays somewhere, or our latency model changed (or was off in the
 first place). Though I continue to be impressed with Shadow's accuracy
 here in the face of so many things that could go wrong.

 I'm going to review Shadow's packet code and perhaps run one more
 experiment here.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6401#comment:7>
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