[tor-talk] Double-checking a couple questions about node churn rate

Jeremy Gillula jeremy at eff.org
Mon Oct 13 19:00:00 UTC 2014

On 10/07/2014 07:04 PM, Karsten Loesing wrote:
> If you want to do some more analysis, fetch the latest consensus
> tarball(s) and write a script that compares contained fingerprints ("r"
> lines) for the churn question and exit policy summaries ("p" lines) for
> the exit-policy-change question:
> https://collector.torproject.org/archive/relay-descriptors/consensuses/
> Parsing libraries are available here:
> https://collector.torproject.org/#libraries
> If you have some interesting results, please feel free to share them here!
If anyone is curious, I went ahead and wrote a quick little Python
script that will analyze consensus files from
(To make life easier you have to flatten the extracted consensus files
into one directory instead of having them separated by different
directories for each day.) The script runs through them and finds the
number of nodes that have disappeared or changed their exit policy, and
writes the data to a csv file. (It's completely unoptimized and does no
error checking--it's definitely not production code.)

The script is attached, as well as the resulting csv file containing
data for September 2014. So how many nodes switch from being relays to
exits or vice versa?

The results show that on average, 0.003% of nodes switch from being
relay nodes to exit nodes in any given 1-hour period, and 0.002% switch
from being exit nodes to relay nodes.

Thanks to everyone for all their help!


| Jeremy Gillula, Ph.D.
| Staff Technologist
| Electronic Frontier Foundation
| (415) 436-9333 x158
| GPG Key ID 0x2CAC7BE9
| @the_zeroth_law
| jeremy at eff.org
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