BitTyrant - A selfish Bittorrent client that improves performance

[inman]

BitTyrant differs from existing clients in its selection of which peers to unchoke and send rates to unchoked peers. Suppose your upload capacity is 50 KBps. If you’ve unchoked 5 peers, existing clients will send each peer 10 KBps, independent of the rate each is sending to you. In contrast, BitTyrant will rank all peers by their receive / sent ratios, preferentially unchoking those peers with high ratios. For example, a peer sending data to you at 20 KBps and receiving data from you at 10 KBps will have a ratio of 2, and would be unchoked before unchoking someone uploading at 10 KBps (ratio 1). Further, BitTyrant dynamically adjusts its send rate, giving more data to peers that can and do upload quickly and reducing send rates to others.

BitTyrant is...

* Fast – During evaluation testing on more than 100 real BitTorrent swarms, BitTyrant provided an average 70% download performance increase when compared to the existing Azureus 2.5 implementation, with some downloads finishing more than three times as quickly.

* Fair – BitTorrent was designed with incentives in mind: if a user is downloading at 30 KBps, they should upload at 30 KBps. However, due to the unique workload properties of many real-world swarms, this is not always enforced. BitTyrant is designed to make efficient use of your scarce upload bandwidth, rewarding those users whose upload allocations are fair and only allocating excess capacity to other users.

* Familiar – BitTyrant is based on modifications to Azureus 2.5, currently the most popular BitTorrent client. All of our changes are under the hood. You’ll find the GUI identical to Azureus, with optional additions to display statistics relevant to BitTyrant’s operation.

Anyone gave it a try?
http://bittyrant.cs.washington.edu/

[Ne'tu]

Based on Azureus, let's see how it's workng in the real world.

[pECi]

sounds nice...might give it a try to see how it goes

[Hanz™]

That was done as a project in CS on how to cheat on bittorrent.
Look at the PDF! There is stuff that is labelled: "4.3 Additional cheating strategies".

Cheating might work when there are only few people doing it, but it will just make everything slower if everybody does it. And private sites will ban you for doing so!

[Ne'tu]

Hmmm, this is not a cheating client. I've looked through the PDF, but it's not about cheating there.

[pECi]

well who said anything about using it on a large scale

[Ne'tu]

I think they only want to improve performance of the normal Azureus client. Source code is of course available...

[SIMRACK]

i think this client is banned from oink and bitmetv

[Hanz™]

"Based on the insights gathered from a simple model of
BitTorrent's altruism, we built BitTyrant, a selfish client
that cleverly selects peers so as to optimize the amount
of download per unit of upload bandwidth. We found
that BitTyrant improves performance for all peers that
use it. Nevertheless, in practice, BitTyrant will hurt the
performance of individual swarms as high capacity peers
reach a point of diminishing returns and are incented to
either withhold their upload contribution or invest it in
other swarms. Low capacity peers do not enjoy such a
luxury. As the majority of peers have low capacity, they
will see degraded performance compared to BitTorrent
today."

meh.

edit: And yes, most large private trackers do not like such clients to be used as it deviates from the original bittorrent specification.

[inman]

Private trackers are certainly going to ban this client. But it might come in handy with sites like demonoid where you have lots of peers but still won't connect to any.