[tor-bugs] #13658 [Onionoo]: Onionoo reports Bridge "advertised_bandwidth" as zero when "Bandwidth" is non-zero (was: discrepancy in Onionoo and bridge DB)

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#13658: Onionoo reports Bridge "advertised_bandwidth" as zero when "Bandwidth" is
non-zero
-------------------------+----------------------
     Reporter:  eli      |      Owner:  karsten
         Type:  defect   |     Status:  assigned
     Priority:  normal   |  Milestone:
    Component:  Onionoo  |    Version:
   Resolution:           |   Keywords:
Actual Points:           |  Parent ID:
       Points:           |
-------------------------+----------------------

Comment (by isis):

 Replying to [ticket:13658 eli]:
 > Onionoo gives for my bridge:
 > ["Fast","Running","Stable","Valid"],"last_restarted":"2014-10-16
 19:14:12","advertised_bandwidth":0,"platform":"Tor 0.2.5.8-rc on Windows
 7","pool_assignment":"email ip=4 flag=stable port=443"}
 >
 > @type bridge-network-status 1.0 gives:
 > s Fast Running Stable Valid
 > w Bandwidth=40
 >
 > Shouldn't the BWs both be 0 for a bridge in an email pool?

 I don't know what processing goes into the creation of Onionoo's JSON.
 Karsten would probably be better able to answer that question. However,
 with respect to the `w Bandwidth=40` line, from the end of §3.4.2 of
 `torspec.git/dir-spec.txt`:

 {{{
    The bandwidth in a "w" line should be taken as the best estimate
    of the router's actual capacity that the authority has.  For now,
    this should be the lesser of the observed bandwidth and bandwidth
    rate limit from the router descriptor.  It is given in kilobytes
    per second, and capped at some arbitrary value (currently 10 MB/s).
 }}}

 So, looking at your `bandwidth` line from the `@type bridge-server-
 descriptor`:

 {{{
 bandwidth 98304 196608 40654
 }}}

 From §2.1.1 in `dir-spec.txt`:

 {{{
     "bandwidth" bandwidth-avg bandwidth-burst bandwidth-observed NL

        [Exactly once]

        Estimated bandwidth for this router, in bytes per second.  The
        "average" bandwidth is the volume per second that the OR is willing
 to
        sustain over long periods; the "burst" bandwidth is the volume that
        the OR is willing to sustain in very short intervals.  The
 "observed"
        value is an estimate of the capacity this relay can handle.  The
        relay remembers the max bandwidth sustained output over any ten
        second period in the past day, and another sustained input.  The
        "observed" value is the lesser of these two numbers.
 }}}

 It isn't exactly clear, when §3.4.2 says ''"...bandwidth rate limit"'',
 whether it is referring to the `bandwidth-avg` or the `bandwidth-burst`
 ('''note: torspec might need clarification'''). But, fortunately, in this
 case it doesn't matter, because the `bandwidth-observed` (`40654`) is less
 than the others. So, this answers where the rather random `w Bandwidth=40`
 line comes from. :)

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13658#comment:5>
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