Harvard Develops P2P Client that uses Bandwidth as “Currency”

Written by Ernesto on August 30, 2007

Harvard researchers have teamed up with the Tribler team to work on a P2P client with BitTorrent support that uses bandwidth as a global currency. They released Tribler V4.1 yesterday.

Yes, Harvard, the richest University in the world recently started a new line of P2P research. They have an army of law professors to protect them, so unlike others, they must feel safe to do this controversial research in the land of the free and the home of the RIAA/MPAA.

The Harvard project is all about a fresh new approach. To be honest, have we seen a new trick since eMule and Bittorrent started? Things have clearly slowed down in the last years.

The Harvard researchers are currently working on one of hardest P2P problems, ensuring uploads. P2P dies or thrives depending on how much upload people donate. By introducing electronic “currency” for uploads they think they can make P2P HDTV Video on Demand possible. With the minor detail that we all have to switch to their client…

The latest version of Tribler enhances the standard tit-for-tat BitTorrent algorithms with something they call the give-to-get algorithm (PDF article). This new algorithm allows their users to benefit from a good ratio without using a central server like private BitTorrent trackers do.

Tribler users can still join every BitTorrent swarm and play the tit-for-tat game with old-school BitTorrent users. But, when they meet another Tribler peer they switch to give-to-get mode where the currency meter is running. This turns the Tribler network into a private Tracker network without the central server. This basically means, the more you share, the faster your downloads will go.

Every Tribler client keeps an eye on MByte counts of fellow peers. They gossip around about who is a leecher and who is a top dog, without the details of which Hollywood movie it was. The only information displayed about this in the GUI is a list in your profile of the “Top 10 Tribler Uploaders”. For the next version of Tribler they plan to turn that list of top dog uploaders into a decentralized trust system and enable users to correct typos and add tags to the content. In short, BitTorrent would go “2.0″.

But let’s first see if they can really handle network pollution and spam without a central server. It will be quite tricky to get such “Google PageRank” trust algorithms working in P2P.

tribler

Previously: ‘Heroes’ Star Recognizes Benefits of BitTorrent

Next: Jamendo: Download Thousands of Free and Legal Music Albums

63 Responses

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1 Aug 31, 2007 at 01:20 by Bram Cohen

This will never work. Tit-for-tat is perfect. Give-to-get won’t work because the top dogs would take all the upload for themselves, thus you get no swarm.

2 Aug 31, 2007 at 01:23 by Karthik Kastury

@Bram : No I guess this is the way to go to reduce excessive leeching on bit torrent.

3 Aug 31, 2007 at 01:24 by di0rz`

the software crash when i Launch it on OsX. sounds quite pointless anyway.

4 Aug 31, 2007 at 01:38 by Bram Cohen

@Karthik Kastury

When you get no swarm, you get no leeching also, I guess. :)

5 Aug 31, 2007 at 01:57 by Heymbit

When I try to launch it on OSX it also crashes X_X. Oh, little note, Harvard isn’t the first to do this. TvTorrents uses your upload bandwith as currency. No ratio, but whenever you download you lose credits, when you upload you gain them. You have to have a certain number of credits to start and maintain a download forcing you to upload. It’s really neat. Also, upload a lot more than you download and you get faster speeds and can download more at once.

6 Aug 31, 2007 at 02:03 by brian

looks like brad cohen’s mad because HE didn’t develop bittorrent 2.0 hahaha

bittorrent, or at least utorrent, gives you better download speeds depending on your ratio IIRC so leachers don’t always get the fastest speeds. this way does seem more efficient though. let’s see how it plays out

7 Aug 31, 2007 at 02:07 by John M

With all respect to Bram: come on, how much leeching goes on all the damn time out there with tit-for-tat today? Private trackers tend to give a world of better experience than the constant plague of hit and runners … which is human nature after all once they’ve finished their downloads.

Ratio enforcement has been an issue for ages now; including hacked clients which try to screw the trackers. Decentralised trust ranking and record seems like a great idea if only it can be implemented well. Or at least it seems like a candidate.

One problem I see is the IP drift all cable modem users are subject to. And it’s the ocean of asymmetrical pipes through cable modems which gives rise to ratio issues in the first place. Seriously: most of us have to spend 5-10x as long as a seeder than a leech to hit 1:1. Do all of us do it? Hell no. How much that’s hurting torrents overall is an open question.

8 Aug 31, 2007 at 02:49 by Bram Cohen

@Brian

No, I’m not mad. :) I’m somewhat amused by this whole idea, too bad it’ll fail miserably. Let’s for the sake of argument assume that I have a gigabit upstream, which I actualy do, not that you have to believe me. How many people with a single megabit upstream does it take to compete with me? How can anyone beat my dozen seedboxes? People share because they care, not because of ratio enforcement.

And, no. uTorrent and Mainline do not give you any faster downloads if you have a high ratio. If you don’t believe me, just check out network statistics and snoop around wireshark to see what is actualy going on. :)

@John M

Hit and runners are not the plague. The very idea behind BT is sharing the wealth. If someone cannot seed back what they’ve downloaded, is that the reason to punish them, and to make it impossible for them to download? Have you ever tried to seed back a torrent content that has 250 seeders on each leecher? Do you realy belive that the mathematical model of sharing requires to have so many seeders, or is it because of the private BT trackers and their bussiness of selling upload credit (seling users their own bandwidth)?

I wish the Tribler team the best of luck. They’re going to need it. :)

Over and out.

9 Aug 31, 2007 at 04:24 by Anonymous

Though I understand how run-away leechers are a problem, just like John M. pointed out, some of us have suffer from pathetic upload rates and less-than-decent downloads, and even though I’d love to give a fair 1.1 (better 2) ratio, it’d be really difficult unless I left my computer running twenty four hours a day (which I can’t do). My download ranges from 50 - 57kB/s and my (suggested) upload is 11kB/s, I’d have to upload for fives times my download ETA. When/if I download things over 1Gb, I’m already talking about many long hours of uploading, and I’m sure many people suffer from said uneven download/upload, it’d be slightly discriminatory to those without grand connections.

It has also become a problem, personally, that for some reason, uTorrent is slowing down my download (for normal internet browsing) when I leave it to just seed (which I try to do as often as possible). I’ve already modified all the settings as to not cap my upload and supposedly allow a “free” browsing experience while uploading but it’s slowing it down significantly (pages loading anywhere from 4kB/s to 15kB/s where as before it’d allow me to reach 40kB/s, sometimes reaching 50kB/s).

In anycase, unless they can manage to conjure up a way so that the protocol understands these handicaps for some users, it won’t be all too fair.

10 Aug 31, 2007 at 05:28 by Teflon Eyes

The only real problem with BitTorrent is when the swarm dies, the file is no longer available. Project Osprey by ibiblio has already solved this.

http://osprey.ibiblio.org/

11 Aug 31, 2007 at 08:14 by George W. Bush

Bram Cohen is a fake!

12 Aug 31, 2007 at 08:38 by v

leave it up to Harvard to make something into Currency, big shocker there.

this project sounds good on paper, but time will shed more light on this idea.

13 Aug 31, 2007 at 09:09 by Yatti

Well, I wish I could look into this but, being on Rogers SUCKS! Id have to seed like for 10 days to go 1:1 on some items.. Ive sort of prepared for the day Rogers would catch up and im using my good ratio which is decreasing due to not being able to upload) I think issue #1 should be to fix\change the ecryption to stay 1 step ahead of the nasty ISPs… Bram get this an ISP which advertised Bit Torrent at one time and now = excessive throttle on everything.

14 Aug 31, 2007 at 10:45 by Hershey Laney

As far as I know, P2P Torrents are born out of people’s spirit of sharing. Sharing means giving something without expecting something in return. For me, law and technology can never understand that. Those people trying to make money out of free downloads are contradicting their own words. “The more you SHARE, the faster your downloads will go,” eh?

15 Aug 31, 2007 at 11:11 by Derek

This would never work.
Every Internet service provider on Earth would unite and ban the file sharing that supports using upload bandwidth as currency.
As soon as your everyday home broadband Internet connection starts seeding, trying to compete with those whom have much greater upload bandwidth, it would end.
Companies like Comcast would not put up with their subscribers trying to complete with ISPs in western Europe or Japan that on average have 10 times the bandwidth up and down, for less cost.

16 Aug 31, 2007 at 11:12 by Ravi

Makes it easy for the top dogs to get busted and sources lost in an instant.

17 Aug 31, 2007 at 11:17 by Hasan

Well, eMule already works like that!

Upload more, you download faster.

18 Aug 31, 2007 at 12:36 by Gus

With all the problems with our currency-based economy, it’s hard for me to imagine why we would want to emulate it.

Right off the top of my head, I think such a model emphasizes the “currency” over actual sharing. File sharing optimization focuses on increasing general sharing speeds, not on increasing available bandwidth. This is a crucial distinction that will cause this project to tank.

Since optimization occurs as an increase in _actual_ transfer speeds, and not in “potential” speeds (as in the currency model), then naturally the algorithm should address the actual transfers and not the potential ones (I’m using “potential transfers” to refer to bandwidth, which may or may not be used for actual transfers). As Bram has pointed out, the latter model will have wasted bandwidth (e.g. in the “250 seeders to 1 leecher” scenario), since it addresses potential transfers, a.k.a. “bandwidth”, and therefore its subjects may or may not actually materialize as real transfers; the ones that don’t result in wasted bandwidth. Wasted bandwidth = 250 seeders sitting around, wasting resources on both ends, just to keep a good ratio.

Join a private tracker and run a torrent that has a 250:1 s/l ratio and see how long it takes to keep a good d/u ratio. The ratio is not important at all, since leeching without seeding will hardly negatively affect the swarm at all, yet you will still be punished with a poor ratio. Since the focus is on the node’s ratio rather than on the swarm’s sharing efficiency, it results in such a very sub-optimal situation. A good ratio doesn’t necessarily imply efficient file sharing, which is why Bram so vehemently opposes private trackers that focus on ratios.

Read up on game theory and the Prisoner’s Dilemma (which is directly translatable to file sharing). In game theory lingo, the “currency” model focuses on winning matches, not on winning points. For the Prisoner’s Dilemma, tit-for-tat has so far been the best overall strategy. That is a mathematical fact.

19 Aug 31, 2007 at 12:53 by shoung

this won’t work well at all.

Give-to-get sucks

20 Aug 31, 2007 at 13:09 by GG

For Diversity and Creation , I think it’s a good idea.

21 Aug 31, 2007 at 13:26 by Varun S

Good luck to them, because they’ll need some. They’re definitely a setp ahead of Kazaa when using ratings - as Kazaa used local machine to store ratings (easily manipulated) and BT2.0 will use decentralized ratings. LOL. But the problem doesn’t end here. Suppose a hacker creates a BitTyranny2.0 program which floods the swarm with artificial clients that *cheatingly* gossip positive things about you especially when you’re leeching. That would be enough to exploit the ratings system used in BT2.0

So sorry Harvard, but as long as any “currency” is used there will always be counterfeiters.

22 Aug 31, 2007 at 13:55 by John M

@Bram

Very true criticism of the worst side to private trackers. I even saw a pretty decent one I was in once move to enforce an “everyone

23 Aug 31, 2007 at 13:56 by John M

@Bram

Very true criticism of the worst side to private trackers. I even saw a pretty decent one I was in once move to enforce an “everyone less than 1.0 is OUT!” rule … presumably to their own destruction. There are certainly a lot of tracker admins who also happen to be morons out there! The key is to find good ones.

Demonoid is probably the best example of a massive private tracker which keeps functioning AND gives me room to upload to a good ratio without the tyranny of “rare leecher” swarms. I always make a point of prioritising the swarms where my (slow) seed is actually of significance. At Demonoid that means leaving popular ones at 0.1 ratio while sticking with smaller ones well above 5.

@Anonymous #9

I have a one word answer for your problem: Autospeed. Azureus isn’t everyone’s cup of tea, but that function when well tuned is your best friend. Basically it detects when your pipe is getting clogged and throttles the torrents back so browsing etc. still works. Frankly essential for any shared home cable, and frustrating so many good clients like µtorrent don’t feature it.

I have a coder bud who’s building this feature into Transmission (a svelte native Mac client) to save me the bother of Azureus’ Java Achilles Heel. So far it’s testing quite nicely.

@Varun S

Counterfeits indeed. A good point. But notice how counterfeiting still doesn’t force the real world off hard cash? It’s kind of like Google Bombing … sometimes it’s a problem but overall Google and the world’s advanced economies work well. Comes down to balance I expect.

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