Beat me to it. My own implementation is here:
https://github.com/christophebiocca/bitcoin-network-simulator
Same basic principles, but I've been following the protocol message
structure as much as possible/Theoretical support for transaction
propagation (I really want to see zero-conf stuff, and whether it works).
Running a network of 1000 full nodes (with 100 miners) for a week of
simulated time (with a normal hashrate) and empty blocks (except for the
coinbase transaction) takes about 30-60 seconds.
Uses nodejs, with the ultimate goal of having a network/chain visualization
running in the browser (with the actual simulation running on a WebWorker
to keep things responsive).


On Sun, Nov 17, 2013 at 11:43 AM, Rafael Brune <mail@rbrune.de> wrote:

> Over the last days I spent some time working on a simple Bitcoin network
> simulator.
> It is a stochastic event-based continuous-time simulation of Bitcoin miners
> exchanging messages and building block chains. It simulates latency,
> bandwidth
> and also verification speed but it currently does not simulate
> propagation/inclusion
> of transactions and instead uses random block sizes.
>
> The simulator includes two examples, one for a 51% attack and the other is
> an
> implementation of selfish mining (pretty much 1:1 as described in the
> paper).
> With the random parameters I picked it seems like it pays off to mine
> selfish with
> >=30% of the hashing power - but take this with a huge grain of salt as
> this
> is with a very small network and randomly chosen parameters. And of course
> it
> is not a perfect replica of the real world network.
>
> Since this is based on my understanding of the Bitcoin network and
> protocol it
> would be great if others would take a look and help improve it.
>
> The project can be found on my github:
> https://github.com/rbrune/btcsim
>
> Regards,
>  Rafael Brune
>
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