Hello,
For the unaware, we have been working on the design and development of Shadow, a simulator capable of running real binaries over a simulated network, and a plug-in that runs real Tor. Shadow can simulate roughly 1000 Tor nodes in 10 GB of RAM and is easy to setup and use (no root required). You can generate realistic Tor topologies using a consensus, and test changes implemented in Tor extremely quickly.
Earlier this year, I had an idea for a new algorithm on Sunday, thought about how it might work and discussed it with Nick [Hopper - my adviser] on Monday, implemented it in Tor and tested it on Tuesday and Wednesday, started running experiments and had results by Friday.
Honestly. That fast.
If you have the need to run Tor experiments, or are just interested in the Software, please try it out. We would love any feedback or comments or suggestions if you have them!
We are continuously working on improving the simulator, including more efficient use of multiple CPU cores and a command-line interface to help with installing Shadow and some of its dependencies. (Because really, who wants to install dependencies?)
More details on Shadow's design can be found in our technical report: http://www-users.cs.umn.edu/~jansen/papers/shadow-umntr11-020.pdf
A release version that is somewhat stable is available on the Shadow webpage: http://shadow.cs.umn.edu/
Our code is public at https://github.com/shadow
Best regards, Rob
-- Rob G. Jansen U.S. Naval Research Laboratory rob.g.jansen@nrl.navy.mil 202.767.2389