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The P2P Elephant Charles Greenwald for SOASIS 15MAY2001.

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Presentation on theme: "The P2P Elephant Charles Greenwald for SOASIS 15MAY2001."— Presentation transcript:

1 The P2P Elephant Charles Greenwald for SOASIS 15MAY2001

2 2001-05-15SOASIS[2] P2P (peer-to-peer) … is a hot new thing on the internet, but what exactly is it? Is P2P a topology, a technology, a computing model, an ideology, or a way of life?

3 2001-05-15SOASIS[3] We’ll talk about definitions of P2P implementations of P2P unintended consequences of P2P We'll also talk about what to listen for when you hear P2P talk and about what you should expect to hear.

4 2001-05-15SOASIS[4] Topologies - I

5 2001-05-15SOASIS[5] Topologies - II

6 2001-05-15SOASIS[6] Topologies - III

7 2001-05-15SOASIS[7] Topologies - IV

8 2001-05-15SOASIS[8] Definition I - topology "A type of network in which each workstation has equivalent capabilities and responsibilities. This differs from client/server architectures, in which some computers are dedicated to serving the others. Webopedia

9 2001-05-15SOASIS[9] Definition II - technology “This literal approach to peer-to-peer is plainly not helping us understand what makes P2P important”. “If you're looking for a litmus test for P2P, this is it: –1) Does it treat variable connectivity and temporary network addresses as the norm, and –2) does it give the nodes at the edges of the network significant autonomy?” Clay Shirky at O’Reilly

10 2001-05-15SOASIS[10] “… a central server helps make the connection.” (Forrester) –directory (used to find people) AOL Instant Messenger ICQ –index (used to find data) Napster (distinction after GartnerGroup)

11 2001-05-15SOASIS[11] … or not. When you log onto the Gnutella network, you are sort of wading into a sea of people. People as far as the eye can see. And further, but they disappear over the horizon. So that's the analogy. When you log on, you see the host counter start going crazy. That's because everyone in your horizon is saying "Hello" to you. After a while, it stops counting so rapidly, because you've counted most everyone in your horizon. Over time the people in the horizon change, so you'll see the counter move slowly. If you log in another day, you should see a whole bunch of fresh faces, and maybe you'll have waded into a different part of the network. A different part of the crowd. Different information. What is Gnutella?

12 2001-05-15SOASIS[12] Definition III - computing model “The potential of tapping into the unused computer resources sitting around on everyone's desk at home and in the office... to link individual PCs into a virtual supercomputer and harness vast unused processing resources.”

13 2001-05-15SOASIS[13] Definition IV - ideology “Freenet protects freedom of speech by enabling anonymous and uncensorable publication of material ranging from grassroots alternative journalism to banned exposes like Peter Wright's and David Shayler's revelations about MI5.” Ian Clark (Freenet) "I worry about my child and the Internet all the time, even though she's too young to have logged on yet. Here's what I worry about. I worry that 10 or 15 years from now, she will come to me and say 'Daddy, where were you when they took freedom of the press away from the Internet?'" Mike Godwin (EFF) “we need many-to-many media like the Internet, with no central control allowing dictators or corporations to put us all in danger and to throw us back into the Dark Ages … we must fight vigorously against any and all attempts to restrict information freedom on the Net and elsewhere” mission statement

14 2001-05-15SOASIS[14] Definition V - way of life P2P is really person to person –eBay - person to person sales –PayPal - person to person payments –NeetMeeting and AIM- person to person conversation –Napster - person to person file transfer

15 the land of unintended consequences

16 2001-05-15SOASIS[16] the tragedy of the commons “almost 70% of Gnutella users share no files, and nearly 50% of all responses are returned by the top 1% of sharing hosts.... free riding is distributed evenly between domains, so that no one group contributes significantly more than others,... peers that volunteer to share files are not necessarily those who have desirable ones. … free riding leads to degradation of the system performance and adds vulnerability to the system. Free Riding on Gnutella by Eytan Adar and Bernardo A. Huberman

17 2001-05-15SOASIS[17] “YAPUKA” This whole area is reminiscent of, say, nuclear power, or electronic voting, or anything based on Social Security numbers: the technocrats (who do not necessarily have any technical background, even if they are in the private sector) come up with some great scheme that "simply" relies on nobody ever, ever screwing up. (Since most technocrats have never actually done a real job in their lives, they have probably never screwed up either.) This attitude is known in French as "yapuka", short for “il n'y a plus qu'a…”, or “it's easy, all you have to do is…”. Nick Brown, Risks Digest 21.34

18 2001-05-15SOASIS[18] reciprocity “a given file could be hosted (and copies and redundancies built-in) by 10, 200, or 10,000 individual computers, eliminating the need to concentrate spending on backup equipment or on bandwidth or on a central location” Nicholas Mercader

19 2001-05-15SOASIS[19] reliability Downloads that fail show the problem with Mojo's "Swarm Distribution" method: If a chunk of a file is no longer available on any server, you can't get the file. Since the nature of any P2P network is very dynamic, with hosts connecting and disconnecting all the time, this is a major problem. review

20 2001-05-15SOASIS[20] cheating "Fifty percent of the project's resources have been spent dealing with security problems,” “the Seti@home software has been hacked... to make it run faster, to spoof positive results and to make it look more work had been performed to improve leader board rankings” “If people are spoofing Seti@home to enhance their self esteem, what are the chances they will cheat distributed computing projects that pay them for taking part?” David Anderson (SETI@home director)

21 2001-05-15SOASIS[21] getting what you ask for “ShareZilla intercepts every Gnutella search that comes across its network horizon and re-transmits an ad back to the person originating the request.” –open source, no central control, resists censorship...

22 2001-05-15SOASIS[22] the salesman always comes “When you use Napster's servers to allow fellow music lovers access to your MP3 collection, you're also allowing online marketers to peek inside your hard drives to determine your musical tastes -- and to infer from those tastes your interests in a wealth of other products they might want to sell you.”

23 2001-05-15SOASIS[23] tanstaafl Because it is peer-to-peer, Hotline does away with the Internet service provider or central server and provides a direct link between individual computers. The result is a faster, more-efficient exchange of files. P2P also makes it possible to send large files -- pictures or videos -- without having to worry about whether or not the server will accept a file of such size. Marjo Johne

24 2001-05-15SOASIS[24] the garage sale That data which you have bothered to keep on your hard disk is what you found to be valuable. So when you share it you are sharing what is most valuable on the entire Internet. -- What is Gnutella

25 2001-05-15SOASIS[25] the Edsel: what would you pay? "P2P is a particularly comical new coinage for a business model since the phrase starkly points out that there's no middleman -- so how can anyone possibly make any money?" Katherine Mieszkowski, Salon

26 2001-05-15SOASIS[26] information wants to be free “… one can’t have it both ways. Either my node is distinctive and will be missed for some reason when it goes down, or else how have I gained any power in this new P2P Internet? Don’t get me wrong, I prefer the more reliable implementation where my machine provides nothing completely unique. But the I miss exactly how this is supposed to [produce] the ‘democratization’ of the Internet, whatever that might be.” Nancy Collins

27 2001-05-15SOASIS[27] free MIPS: are you going to eat that?

28 2001-05-15SOASIS[28] Napster works because it has: simple implementations the same data on many different PCs static files data such that you don’t mind trusting the person sharing it lots of college students with very fast network connections

29 2001-05-15SOASIS[29] P2P doesn’t work as well with: unique content (when I want your pictures I don’t want to have to call and ask you to boot your PC) content that keeps changing (imagine eBay having all its data stored like Napster) content that requires a trust relationship - Dan Bricklin

30 2001-05-15SOASIS[30] P2P a topology a technology a computing model an ideology a way of life

31 2001-05-15SOASIS[31] tests common resources yapuka reciprocity reliability cheating sales free lunch where’s the value where’s the money

32 2001-05-15SOASIS[32] "a global network that allows communication and files to flow directly from one person's desktop to another, unseen and untouched by any person or company along the way"

33 2001-05-15SOASIS[33] "searching for information... contained not just in websites but also in the hard drives of PCs connected to the network"

34 2001-05-15SOASIS[34] "the potential of tapping into the unused computer resources sitting around on everyone's desk at home and in the office"

35 2001-05-15SOASIS[35] “a given file could be hosted (and copies and redundancies built-in) by 10, 200, or 10,000 individual computers, eliminating the need to concentrate spending on backup equipment or on bandwidth or on a central location” Nicholas Mercader

36 2001-05-15SOASIS[36] "Amway inherently has P2P built into its business” Nicholas Mercader

37 2001-05-15SOASIS[37] "unofficial groups devise rules and ban people who break them"

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