[tor-bugs] #28588 [Core Tor/sbws]: SBWS 'bw_torflow_scale' does not appear to honor relay MaxAdvertisedBandwidth

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#28588: SBWS 'bw_torflow_scale' does not appear to honor relay
MaxAdvertisedBandwidth
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 Reporter:  starlight      |          Owner:  (none)
     Type:  defect         |         Status:  new
 Priority:  Medium         |      Milestone:
Component:  Core Tor/sbws  |        Version:  sbws: unspecified
 Severity:  Normal         |     Resolution:
 Keywords:                 |  Actual Points:
Parent ID:                 |         Points:
 Reviewer:                 |        Sponsor:
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Comment (by juga):

 Replying to [ticket:28588 starlight]:
 > Examining the current 1.0.2 branch it does not seem bw_torflow_scale()
 honors MaxAdvertisedBandwidth.

 If i understood it correctly, torflow does not use the descriptor average-
 bandwidth, but observed-bandwidth. Is that correct?.

 > I'm having trouble following the path the data element follows through
 the (not simple) code.

 There's #28282 to refactor that.

 > Is clearly visible with comments in bw_sbws_scale() expressed as
 `min(l.desc_bw_avg, l.bw * scale_constant / m)` where `desc_bw_avg` is the
 max advertised value but cannot determine this value is consumed by
 bw_torflow_scale() or anywhere else.

 No, it's not consumed anywhere else.

 BTW, one comparison we didn't made was to compare torflow's scaling with
 the linear scaling using the observed bandwidth.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28588#comment:2>
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