[tor-bugs] #17810 [Core Tor/Torflow]: TorFlow should ignore self-reported bandwidths when measuring relays

[Tor Bug Tracker & Wiki]

#17810: TorFlow should ignore self-reported bandwidths when measuring relays
------------------------------+------------------------
 Reporter:  robgjansen        |          Owner:  (none)
     Type:  defect            |         Status:  new
 Priority:  Medium            |      Milestone:
Component:  Core Tor/Torflow  |        Version:
 Severity:  Normal            |     Resolution:
 Keywords:                    |  Actual Points:
Parent ID:                    |         Points:
 Reviewer:                    |        Sponsor:
------------------------------+------------------------

Comment (by robgjansen):

 > While Torflow votes are unitless, they resemble actual bandwidths owing
 that they are interpretations of bandwidth measurements taken at each
 node.

 Careful here. I think TorFlow measures something closer to residual
 bandwidth capacity at the time of the measurement, not the full capacity
 of the link. And it doesn't even measure residual capacity exactly,
 because of scheduling and fairness. For example, if my relay is operating
 at 100% link utilization and TorFlow tries to measure it, TorFlow isn't
 going to get 0 bandwidth and it isn't going to get 100% bandwidth; TorFlow
 is probably only going to get roughly 1/N of my bandwidth where N is the
 number of other active flows.

 Or am I misunderstanding and the authorities interpret the measurements
 differently?

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17810#comment:18>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online