Opened 4 weeks ago

Last modified 4 weeks ago

#32126 new enhancement

Add OONI's Vanilla Tor measurement data to Tor Metrics

Reported by: karsten Owned by: metrics-team
Priority: Medium Milestone:
Component: Metrics/Ideas Version:
Severity: Normal Keywords:
Cc: metrics-team, hellais, phw, gaba Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

OONI has a test called Vanilla Tor which "attempts to start a connection to the Tor network. If the test successfully bootstraps a connection within a predefined amount of seconds (300 by default), then Tor is considered to be reachable from the vantage point of the user. But if the test does not manage to establish a connection, then the Tor network is likely blocked within the tested network."

We should get these measurements into Tor Metrics.

I spent the last couple days on downloading a copy of the OONI metadata database and extracting useful data from it. I'll add some results after the lunch break.

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vanilla-tor-bootstrap-2019-10-17-a.png (143.0 KB) - added by karsten 4 weeks ago.
vanilla-tor-bootstrap-2019-10-17-b.png (169.5 KB) - added by karsten 4 weeks ago.
vanilla-tor-bootstrap-2019-10-17-c.png (273.2 KB) - added by karsten 4 weeks ago.

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Change History (6)

Changed 4 weeks ago by karsten

Changed 4 weeks ago by karsten

Changed 4 weeks ago by karsten

comment:1 Changed 4 weeks ago by karsten

Here are the results from my analysis in the past few days:


This first graph shows all measured times until 100% bootstrapped between 2016-01 and 2019-10. Some observations:

  • 50% of measurements were done in under 15 seconds, and roughly 90% finished in under 1 minute.
  • There's a bump shortly after 120 seconds, which is most likely the result of a 120 second timeout somewhere in the process.
  • A few percent of measurements did not succeed within the test timeout of 300 seconds: the line is not at 100% at the 300 seconds mark but roughly at 97%.


The second graph shows different stages of the bootstrap process. Again some observations:

  • It's not entirely clear (to me) why 0% bootstrapped is not just a vertical line at the 0 s mark. If it requires work to get to 0%, it's not 0% but rather 2%, 1%, or 0.5% of the process. Maybe a naming issue, possibly a measurement issue. At least all measurements succeed at bootstrapping to 0% within the test time.
  • The 20% line has a small bump right after 120 s, so there must be a 120 s timeout for this early bootstrap phase. There's another bump at roughly 130 s which could be due to the same 120 s timeout that was started later.
  • The 80% and 100% line are almost the same. If a client makes it to 80%, it's just a matter of seconds to get to 100%.


The third graph shows the same data broken down by country for the slowest 5 countries. Observations:

  • Most measurements in China and Egypt did not proceed past the 0% bootstrapped point.
  • Almost none of the Kazakhstan succeeded, even fewer than in China and Egypt. The 20% bootstrapped line looks really funny, starting to increase only after full 2 minutes. Maybe these measurements would succeed after 10 or 20 minutes, which is something we won't find out from this data.
  • Belarus has two visible bumps shortly after 2 and 4 minutes. I would guess that there'd be more bumps after 6 and 8 and 10 minutes. Maybe this is related to some subset of relays not being reachable.
  • Turkey has roughly 1/4 of measurements not succeeding, with the remaining ones looking slow-but-okay. The reason might be that we're looking at almost 3 years of measurements here, and maybe bootstrapping succeeded in 75% of the time and did not succeed in 25% of the time.

The next step here is to discuss what results we want to add to Tor Metrics. Are these graphs useful, or is there something potentially more interesting in the data that we want to have? I'm hoping for input from other teams here.

All graphs above are ECDFs, unlike other graphs on Tor Metrics. This is a smaller issue on the graphing side, because we need to process non-aggregated measurements for making a graph. It's also a possible issue on the usability side, because ECDFs are probably harder to understand than time plots.

The next step after answering the questions above is to figure out how we'd get the data for these new graphs. Some thoughts:

  • Maintaining our own copy of the OONI metadata database, like I did for this analysis, isn't feasible. We only need a small fraction of ~40G of this database which currently has a total size of 696G. Also, cloning this database took way too long for us to do it once per day.
  • We might be able to maintain a copy of the .yaml files of vanilla_tor measurements only. We would sync these once or twice per day and serve them with CollecTor. We'd have to define our own database schema for importing and aggregating them. This is not a small project and not a small commitment.
  • A while ago we were hoping to get a .csv file from OONI with just the data we need. For example, the .csv file behind the three graphs above is 150M large, though it could easily be reduced to 75M, uncompressed. Maybe we'd have to define precisely what data we want (the discussion above) and then write the database query for it. This would be the smallest project and commitment from our side; in other words, it would be most likely to happen soon.
  • A possible variant of the ideas above would be that we operate on a read-only copy of the metadata database where we can define views, run queries, and export results as .csv files.

It would be great to hear from OONI folks which of these approaches would work.

comment:2 Changed 4 weeks ago by karsten

Cc: phw added

comment:3 Changed 4 weeks ago by gaba

Cc: gaba added
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