One of the key tenants of BitTorrent is that you have to contribute (upload) to receive (download). BitTyrant is a new client that finds a way to be selfish within the BT protocols by selectively uploading to peers based on their upload capacity. It was created by researchers to test the robustness of BT’s incentives. From their site:
BitTyrant is a new, protocol compatible BitTorrent client that is optimized for fast download performance. 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.
If you use this, then you will get a faster download. If someoneelse in a swarm uses this then you will get a slower download. If everyone in a swarm uses it then everyone gets decreased performance. Doesn’t sound like a pretty picture to me. Will this spark a BT client arms race where suddenly every client has a “selfish” mode? Will this cause a change in the way companies choose to use BT?
Update: I want give props where props are due. I learned about BitTyrant via TorrentFreak.
Update 2: MonkeyBites has a well-done post discussing BitTyrant and BitThief. BitThief is a nasty piece of software that makes pretend it is a new client and never uploads anything. It is leech only. Torrentfreak has the numbers on how this turns out to not be as effective as one might suppose at first blush.