The document discusses peer-to-peer (P2P) systems, highlighting their evolution following the shutdown of Napster and the rise of alternatives like Gnutella. It explores the potential applications of P2P beyond file sharing, including legal contexts and broadcasting, and addresses the complexities of cooperative behavior among users. Furthermore, it identifies business opportunities within the P2P ecosystem and emphasizes the importance of community engagement and innovation in driving the adoption of P2P technologies.

1. Peer-to-Peer
Introduction to a New Set of Opportunities
Gwendal Simon
Department of Computer Science
TELECOM Bretagne
Jan. 2008

2. 2/ 17
Birth
Context : Napster Shutdown Server
• early adopters are addicted
• early majority is just joining
0 1 2 3 4 5
• legal perspectives are dark
Gwendal Simon : Peer-to-Peer

3. 2/ 17
Birth
Context : Napster Shutdown Server
• early adopters are addicted
• early majority is just joining
0 1 2 3 4 5
• legal perspectives are dark
15
04
03
Gnutella : Serverless Napster 13
02 00
01
• simple but bad idea 11
09
12 19
• just a piece of software
07
06 14
05
• viral bazaar diffusion 18
16 10 08
17
Gwendal Simon : Peer-to-Peer

4. 2/ 17
Birth
Context : Napster Shutdown Server
• early adopters are addicted
• early majority is just joining
0 1 2 3 4 5
• legal perspectives are dark
15
04
03
Gnutella : Serverless Napster 13
02 00
01
• simple but bad idea 11
09
12 19
• just a piece of software
07
06 14
05
• viral bazaar diffusion 18
16 10 08
17
Gwendal Simon : Peer-to-Peer

5. 3/ 17
Gwendal Simon : Peer-to-Peer

6. 4/ 17
Peer-to-Peer is not only File Sharing
. . .but also large-scale legal applications :
• where peers just have to be introduced : phone, storage. . .
• where server become bottleneck : broadcasting. . .
• where nobody should be responsible : virtual world, forums. . .
Gwendal Simon : Peer-to-Peer

7. 4/ 17
Peer-to-Peer is not only File Sharing
. . .but also large-scale legal applications :
• where peers just have to be introduced : phone, storage. . .
• where server become bottleneck : broadcasting. . .
• where nobody should be responsible : virtual world, forums. . .
Attractive Issues : no governance, nor understanding
• academic : what exactly is scalable ?
• developers : is the Bazaar consistent ?
• users : what is the value when I contribute ?
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Part I
Is there any Opportunity in the Bazaar ?
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Motivations
network empirical law value per user global value
broadcast (TV) Sarnoff 1 n
one-to-one (phone) Metcalfe n n2
peer-to-peer Reed 2n 2n
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Motivations
network empirical law value per user global value
broadcast (TV) Sarnoff 1 n
one-to-one (phone) Metcalfe n n2
peer-to-peer Reed 2n 2n
Stirring up a community is the actual challenge :
• aggregate a vast population
• incite them to contribute
⇒ joining an existing community may be far easier
(1047 projects referenced in Sourceforge)
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11. 7/ 17
Yahoo’s Gnutella Developer Forum
"a forum for active Gnutella developers without distractions"
• developers from a company hosting an "official" client
• independent open-source developers
• just some curious guys. . .
Emerging usage : normalization forum
• protocol update, feature proposal, idea exchanges
• Collateral usage : innovation center
• feedback from users : chunk swarming
• external opportunities : URN by Bitzi
• technical development : bootstrap, NAT traversal
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Innovator’s Dilemma
Cooperative or competitive behavior ?
• actors are competitors : have to differentiate
• the value is in Gnutella usefulness : have to cooperate
Conciliate gain for the user and progressive adoption
• no innovation should require full agreement
• for most innovations, gain grows with the number of adopters
• individual innovations (e.g. ergonomics) allow differentiating
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Business Opportunity
A complex ecosystem :
• leery of market economy :
• bazaar culture implies free software
• contributors are reluctant to pay
• but attractive :
• several millions of active users
• a technophile population of online influencers
Requires a hook mixing technical expertise and social understanding
• out of the peer-to-peer system
• but in the peer-to-peer activities
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Part II
When Academic Studies Become Reality
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Peer-to-Peer Fundamentals
28 10
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30 27 17 12 04 26
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29 25 06
09 21 13
31
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Peer-to-Peer Fundamentals
28 10
15 07
30 27 17 12 04 26
18 03 01
29 25 06
09 21 13
31
16
00 19
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23 02 05
08 14 24
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→ each peer chooses some direct neighbors among all peers
=⇒ it creates an overlay
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Peer-to-Peer Fundamentals
28 10
15 07
30 27 17 12 04 26
18 03 01
29 25 06
09 21 13
31
16
00 19
22 11
23 02 05
08 14 24
20
→ each peer chooses some direct neighbors among all peers
=⇒ it creates an overlay
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18. 12/ 17
Few Mature Works
Scientists have focused on few services :
• diffusion of large files (bit-torrent)
• distributed hash tables (DHT) :
• store a pair (key, resource) in the system
• give the key, retrieve the related resource
• if a resource has been stored, it must be accessible
Attractive implementations for controlled network :
• server farm : managing a vast amount of resources
• content delivery network (CDN) : pushing contents
• network of boxes : the new eldorado
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DHT Principles (Chord)
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20 12
21
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23 09
08
25 07
06
28 04
30 02
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39 57
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47 50
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DHT Principles (Chord)
16
19 18 14 13
20 12
21
10
23 09
08
25 07
06
28 04
i + 24 i + 23
30 02
31 01
32 00
33 63
i + 25
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39 57
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47 50
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DHT Principles (Chord)
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19 18 14 13
20 12
21
10
23 09
08
25 07
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28 16 → 50
04
02 → 06
30 02
31 01
32 50 → 02 00
33 63
37
39 57
41
44
47 50
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Business opportunities
Any cost reduction on existing services ?
• one overlay per need : initial development may be costly
• decreasing server cost : gain for large-scale systems
But new services are possible :
• lightweight and immediately worldwide
• relying on networking skills
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Part III
Conclusive Thoughts
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I&R activities on peer-to-peer
Few projects claim studying peer-to-peer :
• Solipsis : a bazaar peer-to-peer virtual world
• P2P-images : a industrial peer-to-peer streaming system
However many academic skills on peer-to-peer in Bretagne :
• computer sciences : world-class teams at IRISA and Telecom Bretagne
• social and human sciences : M@rsouin gathers high-level institutes
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A Shift
Along with Web2.0 trend :
• capturing money requires complex models
• empower a community → beta web-based eye-candy
• both technical and social wow effect
Also a deep scientific trend :
• toward “one billion computers per human”
• balancing power between edges and core network
Gwendal Simon : Peer-to-Peer

26. 17/ 17
A Shift
Along with Web2.0 trend :
• capturing money requires complex models
• empower a community → beta web-based eye-candy
• both technical and social wow effect
Also a deep scientific trend :
• toward “one billion computers per human”
• balancing power between edges and core network
Few possible projects :
• self-administered network : distributed package management
• mixed reality : distributed “1.5 life”
• tangible gifts : distributed Wikipedia
Gwendal Simon : Peer-to-Peer