Hi all!
During the last weeks I have been very busy working on my GSoC project which is about reducing the RTT of preemptively built circuits.
There is now a single script called "rttprober"[0] that depends on a patched[1] Tor client running a certain configuration[2]. The goal is to measure RTTs of Tor circuits. It takes a few parameters as input: an authenticated Stem Tor controller for communication with the Tor client, the number of circuits to probe, the number of probes to be taken for each circuit and the number of circuits that should be probed concurrently. It outputs a tar file containing lzo-compressed serialized data with detailed node information, all circuit- and stream-events involved and the circuit build time for further analysis. Since the RTT-measurements are run in parallel with very short locks it is important not to overload Tor nodes. Therefore a single node is not probed more than once at a time.
A first analysis of some measurements taken supports the original assumption that a Frechét distribution fits both the circuit build times[3] and round trip times[4].
I will continue gathering and analyzing measurement data and will hopefully be able to draw some conclusions from that.
Best, Robert
[0] https://bitbucket.org/ra_/tor- rtt/src/1127f6936086664981fc55b4dbc82b1570714140/rttprober.py?at=master [1] https://bitbucket.org/ra_/tor- rtt/src/1127f6936086664981fc55b4dbc82b1570714140/patches?at=master [2] https://bitbucket.org/ra_/tor- rtt/src/1127f6936086664981fc55b4dbc82b1570714140/torrc?at=master [3] http://postimg.org/image/je8k5yydt/ [4] http://postimg.org/image/ktk90vxm7/