[tor-dev] Status report - Stream-RTT

ra r_a at lavabit.com
Sat Jul 27 00:53:18 UTC 2013

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 

I will continue gathering and analyzing measurement data and will hopefully be 
able to draw some conclusions from that.


[0] https://bitbucket.org/ra_/tor-
[1] https://bitbucket.org/ra_/tor-
[2] https://bitbucket.org/ra_/tor-
[3] http://postimg.org/image/je8k5yydt/
[4] http://postimg.org/image/ktk90vxm7/

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