[tor-bugs] #33009 [Core Tor/sbws]: sbws bandwidth scans should require a minimum exit bandwidth

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#33009: sbws bandwidth scans should require a minimum exit bandwidth
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 Reporter:  teor                                 |          Owner:  (none)
     Type:  defect                               |         Status:  new
 Priority:  Medium                               |      Milestone:  sbws:
                                                 |  1.1.x-final
Component:  Core Tor/sbws                        |        Version:  sbws:
                                                 |  1.1.0
 Severity:  Normal                               |     Resolution:
 Keywords:  sbws-majority-blocker, easy, intro,  |  Actual Points:
  sbws-roadmap                                   |
Parent ID:  #33121                               |         Points:  1
 Reviewer:                                       |        Sponsor:
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Comment (by teor):

 Replying to [comment:5 juga]:
 > i've not checked which consensus weight corresponds to 600Kbyte/sec
 advertised bandwidth.
 > i'm not sure what teor meant with "top 75% of exits", ie. which
 bandwidth value they think about there.
 > Looking https://metrics.torproject.org/rs.html#toprelays, showing 100
 relays per page, it says "Top Relays by Consensus Weight", the bandwidth
 column says "Advertised bandwidth", the first relay in the 3rd page (~1/3
 ~= 75%) shows 58.1 MiB/s.
 > We should look which is the actual consensus bandwidth of that 1st
 relay, if we want to use a hardcoded minimum value.
 > Instead of that i'd suggest, since bandwidth values changes and we
 choose exits based on consensus weight, is that:
 > 1. create a method in relaylist that order them by consensus weight.
 >    You could based it `RelayList.exits`, then order them
 `sorted(self.relays, key=lambda r: r.consensus_bandwidth)`
 > 2. calculate which would be the relay that corresponds to the 75% in
 that order
 > 3. use that value as the minimum value

 Yes, I meant a calculated value.

 Ideally, we should calculate the value each time we get a new consensus.
 If we recalculate it for every circuit, it might slow down sbws circuit
 building.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33009#comment:6>
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