Hi,
I understand that the current bandwidth measurement system is far from ideal, but I am wondering about how the current system works. Does each bandwidth authority also run a bandwidth scanner? Or is it possible that the results from a bandwidth scanner is supplied to multiple authorities?
Thanks! Rob
On Fri, Mar 23, 2018 at 08:13:59PM -0400, Rob Jansen wrote:
I understand that the current bandwidth measurement system is far from ideal, but I am wondering about how the current system works. Does each bandwidth authority also run a bandwidth scanner? Or is it possible that the results from a bandwidth scanner is supplied to multiple authorities?
I believe there are no scanners that supply answers to multiple directory authorities.
You could in theory check whether this is true in practice by seeing if any dir auths vote the same numbers.
I think in past bwauth sessions at meetings, people have made lists of who runs which bwauth.
I think moria1 runs its own, and Faravahar runs its own. I've lost track of the others, but I'd guess that bastet also runs its own, and that maatuska pulls numbers from a bwauth that tjr runs.
https://consensus-health.torproject.org/#bwauthstatus
--Roger
On Fri, Mar 23, 2018 at 08:21:38PM -0400, Roger Dingledine wrote:
On Fri, Mar 23, 2018 at 08:13:59PM -0400, Rob Jansen wrote:
I understand that the current bandwidth measurement system is far from ideal, but I am wondering about how the current system works. Does each bandwidth authority also run a bandwidth scanner? Or is it possible that the results from a bandwidth scanner is supplied to multiple authorities?
[...]
I think in past bwauth sessions at meetings, people have made lists of who runs which bwauth.
Not the original question Rob asked, but a year ago there was a session and the (reformatted) notes contain:
longclaw: hongkong -> US moria: US->US matuska: .se->us faravahar: us->us sebastian: de->de
https://trac.torproject.org/projects/tor/wiki/org/meetings/2017Amsterdam/Not...
(I don't know why there is a sebastian instead of a gabelmoo).
Obviously the situation has changed a bit since then. I don't know if any of the bwscanner locations changed, either (not including losing longclaw and sebastian and adding bastet).
On Mar 23, 2018, at 8:21 PM, Roger Dingledine arma@mit.edu wrote:
I believe there are no scanners that supply answers to multiple directory authorities.
Great! IIRC, at one point in the distant past this was not the case.
You could in theory check whether this is true in practice by seeing if any dir auths vote the same numbers.
Did that; nobody is voting the same numbers. So presumably that means all bwauths are using independent numbers.
I was concerned because bastet and moria1 both stopped voting anything for each of two of my >2 year old relays during distinct time intervals yesterday. I mean there were missing votes, rather than votes of no or low bandwidth. This caused a consensus of Unmeasured=1 and BW=20 for several hours. See [0] if you want to see what I mean by missing votes - I noticed that this happens in every consensus I viewed for at least some number of relays.
I guess maybe I restarted my relays at just the right time to cause a scanner to go nonlinear or something. Things seem to be back to normal now, though. I'm going to chalk this up as bad error handling in the TorFlow code, because that accusation is easy and generally agreeable :D
I think moria1 runs its own, and Faravahar runs its own. I've lost track of the others, but I'd guess that bastet also runs its own, and that maatuska pulls numbers from a bwauth that tjr runs.
Hmm. I wish we were more transparent about who is running scanners and which bwauths consume results from which scanners. Something to keep in mind for those of us working on next-gen replacement scanners.
On Mar 23, 2018, at 10:02 PM, Matthew Finkel matthew.finkel@gmail.com wrote:
Not the original question Rob asked, but a year ago there was a session and the (reformatted) notes contain:
Thanks Matt! That is useful :)
Best, Rob
[0] Warning, this page is quite large, it contains an entry for every relay in the consensus: https://consensus-health.torproject.org/consensus-health-2018-03-23-11-00.ht...
On 24. Mar 2018, at 13:50, Rob Jansen rob.g.jansen@nrl.navy.mil wrote:
I think moria1 runs its own, and Faravahar runs its own. I've lost track of the others, but I'd guess that bastet also runs its own, and that maatuska pulls numbers from a bwauth that tjr runs.
Hmm. I wish we were more transparent about who is running scanners and which bwauths consume results from which scanners. Something to keep in mind for those of us working on next-gen replacement scanners.
It is at the discretion of the bwauth operator to ensure that they're using a trusted source for their data. To me, that means anything other than running the code myself is utterly unacceptable, other operators might make other choices. I think it makes sense to say that the operator of a given bw auth is *responsible* for whatever they're voting on, whether they run the bwauth themselves or not.
Cheers Sebastian
On Mar 25, 2018, at 12:13 PM, Sebastian Hahn hahn.seb@web.de wrote:
On 24. Mar 2018, at 13:50, Rob Jansen rob.g.jansen@nrl.navy.mil wrote:
I think moria1 runs its own, and Faravahar runs its own. I've lost track of the others, but I'd guess that bastet also runs its own, and that maatuska pulls numbers from a bwauth that tjr runs.
Hmm. I wish we were more transparent about who is running scanners and which bwauths consume results from which scanners. Something to keep in mind for those of us working on next-gen replacement scanners.
It is at the discretion of the bwauth operator to ensure that they're using a trusted source for their data. To me, that means anything other than running the code myself is utterly unacceptable, other operators might make other choices. I think it makes sense to say that the operator of a given bw auth is *responsible* for whatever they're voting on, whether they run the bwauth themselves or not.
I totally agree! Though, I do think that the decisions of which data sources are used could be made public - not as a means to call into question or criticize the choice of the data source, but more as a means to understand how the system works. Eventually (in an ideal world where the scanners report their status) the community could help monitor the health of the scanners. If this makes the job of a bwauth more difficult (we should design it so it doesn't), that should certainly be considered as well.
Best, Rob
On Sat, Mar 24, 2018 at 08:50:18AM -0400, Rob Jansen wrote:
I was concerned because bastet and moria1 both stopped voting anything for each of two of my >2 year old relays during distinct time intervals yesterday. I mean there were missing votes, rather than votes of no or low bandwidth.
I've filed a ticket for what I think is the root cause:
https://trac.torproject.org/25685
There is indeed a bandaid in place so that relays generally recover from this situation, but hopefully we can do even better.
See also https://lists.torproject.org/pipermail/tor-relays/2018-March/014764.html for where a similar thing happened to another relay operator.
--Roger
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Matthew Finkel -
Rob Jansen -
Roger Dingledine -
Sebastian Hahn