Changes between Version 10 and Version 11 of doc/BandwidthAuthorityMeasurements


Ignore:
Timestamp:
Dec 19, 2017, 11:28:19 PM (8 months ago)
Author:
teor
Comment:

Update with goals from bwauthority spec

Legend:

Unmodified
Added
Removed
Modified
  • doc/BandwidthAuthorityMeasurements

    v10 v11  
    99== What does Bandwidth Measurement Optimise? ==
    1010
     11   The goal of the bandwidth authorities is to balance load across the
     12   network such that a user can expect to have the same average stream
     13   capacity regardless of path. Any deviation from this ideal
     14   load balancing can be regarded as error.
     15
     16https://gitweb.torproject.org/torflow.git/tree/NetworkScanners/BwAuthority/README.spec.txt#n353
     17(This spec has not been updated as the code has changed.)
     18
     19So the Tor network should give an equal share of bandwidth to each relay, based on its capacity. But this does not always happen in practice, due to geographical effects: https://atlas.torproject.org/#map (consensus weight vs advertised bandwidth).
     20
     21TODO:
     22* work out how to measure how successful we are
     23
     24=== What other things might we want bandwidth measurement to optimise? ===
     25
    1126Using the Tor network needs to be a good experience for clients. This means:
    1227* maximising throughput, and
    1328* minimising latency.
    1429Different clients have different needs: a SSH or IRC client wants low latency, but a big download wants throughput. Tor 0.2.9.8 and later try to prioritise interactive sessions over bulk transfers.
    15 
    16 Many relay operators think that the goal of bandwidth measurement is to allocate bandwidth equally across all relays.
    17 (Most operators expect the Tor network to give an equal share of bandwidth to their relay.) But clients might have a better experience if they use a smaller number of high-bandwidth relays.
    18 
    19 Here is the original spec for the bandwidth authorities. It has not been updated as the code has changed.
    20 
    21 https://gitweb.torproject.org/torflow.git/tree/NetworkScanners/BwAuthority/README.spec.txt
    22 
    23 TODO:
    24 * confirm that minimising the bandwidth-delay product is one of Tor's goals
    25 * work out how to measure how successful we are
    2630
    2731== What do Bandwidth Authorities Measure? ==