Incentives for Sharing in P2P

1
Incentives for Sharing in P2P

• http//users.ioa.sch.gr/develeg/p2p/p2p-project.ht
  m
• ?as????? ?eße????a
• ?aµp???? ?aµ???

2
P2p networks

• a?t?-???a??s?µa ?deat? d??t?a
• ?ata?eµ?µ??a
• ????? ?e?t???? d?????s? ? ?p?d?µ?

?da???? ?aµ???? ??st??? p?atf??µa a??pt????
efa?µ???? ??a t?? ap? ?????? s??e?sf??? ?a? ???s?
p????
3
The problem

• ?? ???ste? de? ????? a????µ?ta ????t?a ?a
  p??sf????? t??? p????? t??? st? s?st?µa
• 70 Gnutella users share little or no content
• 50 of all requests are satisfied by the top 1
  sharing hosts

Free-riders ???ste? p?? e?µeta??e???ta? p2p
s?st?µata ??a d??? t??? ?fe??? ????? ?a
a?tap?d?d??? p??sf????ta? t??? d????? t??? p?????.
4
The consequences

• ???s????p?a f??t?? (load imbalance)
• ?at????s? t?? p???? t?? ??µß?? p?? s??e?sf?????
  (p.?. bandwidth)
• ?p?ß??µ?s? t?? ?????? ?f??e?a? t?? s?st?µat??
• ????te??? ?????? p????
• ?aµ???te?? ep?d?s? t?? s?st?µat?? (long delays,
  download failures)

tragedy of the commons Each man pursuing
individual utility in a world that is limited
5
Requires

• ????t?a ??a s??e?sf??? ?a? s??e??as?a t?? ???st??
  sta p2p s?st?µata

6
DAMD

• Distributed Algorithmic Mechanism Design (DAMD)
• Combines theoretical computer sciences
  traditional focus on computational tractability
  with more recent interests in incentive
  compatibility (economics study) and distributed
  computing
• ? Multi-agent ?ata?eµ?µ??? µ??f? t?? ??ad??t???,
  t?? p??sd?de? ?a?a?t???st??? t?s? e??? s?st?µat??
  ??????µ?a? ?s? ?a? e??? ?p?????st?.
• ?e t? Mechanism design µe?et?ta? ? s?ed?asµ??
  s?st?µ?t?? ?ts? ?ste ? ?d??te??? s?µpe??f??? t??
  ??µß?? ?a ?ata???e? st??? ep???µ?t??? st????? t??
  s?st?µat??.

7
??ß?????af?a

• Incentive models based on Game Theories
• B. Cohen. Incentives Build Robustness in
  BitTorrent. Workshop on Economics of Peer-to-Peer
  Systems, 2003
• C. Buragohain, D. Agrawal, S. Suri. A Game
  Theoretic Framework for Incentives in P2P
  Systems, International Conference on Peer-to-Peer
  Computing, 2003
• K. Ranganathan, M. Ripeanu, A. Sarin and I.
  Foster, To Share or not to Share An Analysis of
  Incentives to Contribute in Collaborative File
  Sharing Environments, Workshop on Economics of
  Peer-to-Peer Systems, Jun, 2003
• M. Feldman, K. Lai, I. Stoica, J. Chuang. Robust
  Incentive Techniques for Peer-to-Peer Networks.
  Proceedings of the 5th ACM conference on
  Electronic commerce. May 2004.
• K. Lai, M. Feldman, I. Stoica, J. Chuang.
  Incentives for Cooperation in Peer-to-Peer
  Networks. Workshop on Economics of Peer-to-Peer
  Systems, 2003.
• J. Shneidman, and D. Parkes. Rationality and
  Self-Interest in Peer to Peer Networks. In Proc.
  IPTPS 03, Berkeley, Feb. 2003.

8
??ß?????af?a

• Pricing Economic Models
• T.W. Ngan, D. Wallach, P. Druschel. Enforcing
  Fair Sharing of Peer-to-Peer Resources.
  Proceedings of the Second International Workshop
  on Peer-to-Peer Systems (IPTPS '03). February
  2003
• K. Tamilmani, V. Pai, and A. E. Mohr. SWIFT A
  System With Incentives For Trading. Proceedings
  of the 2nd Workshop on the Economics of
  Peer-to-peer Systems. June 2004.
• V. Vishnumurthy, S. Chandrakumar and E. G. Sirer.
  KARMA A Secure Economic Framework for
  Peer-to-Peer Resource Sharing. Workshop on
  Economics of Peer-to-Peer Systems, 2003.
• B. Yang, S. Kamvar, H. Garcia-Molina. Addressing
  the Non-Cooperation Problem in Competitive P2P
  Systems. Proceedings of the First Workshop on
  Economics of P2P systems, 2003.
• N. Christin and J. Chuang. On the cost of
  participating in a peer-to-peer network.
  Proceedings of the 3rd International Workshop on
  Peer-to-Peer Systems (IPTPS04), Feb 2004

9
??ß?????af?a

• Reputation metric
• S. D. Kamvar, M. T. Schlosser, and H.
  Garcia-Molina, Incentives for Combatting
  Freeriding on P2P Networks. Proc. EURO-PAR, 2003

10
??ß?????af?a

• S?µp????µat???
• E. Adar and B. Huberman. Free riding on Gnutella.
  First Monday, 5(10), October 2000.
• S. Saroiu, P. Krishna Gummadi, S. D. Gribble. A
  Measurement Study of Peer-to-Peer File Sharing
  Systems. Technical Report UW-CSE-01-06-02. In
  Proceedings of Multimedia Computing and
  Networking, 2002.
• J. Feigenbaum and S. Shenker. Distributed
  algorithmic mechanism design Recent results and
  future directions. In Proc. 6th Intl Workshop on
  Discrete Algorithms and Methods for Mobile
  Computing and Communications, pages 113,
  Atlanta, GA, September 2002.
• David Hales Simon Patarin, How to cheat
  BitTorrent and why nobody does. Technical Report
  UBLCS-2005-12. May 2005

11
Our project

• ??as??p?s? ep?st?µ?????? ß?ß?????af?a?
• S?????t??s? ß?ß?????af?a?.
• ???t? µe??t? ?a? ta????µ?s? t?? e??as??? s?µf??a
  µe t? µ??t??? p?? p??te?????.

12
?p?µe?a ??µata

• ??? ß???? µe??t? ?a? s???pt??? pe????af? t???.
• ???sd????sµ?? pa?a???t?? efa?µ???? t???, ?a???
  ?a? p?? a?t?µet?p????? ta ?d?a?te?a
  ?a?a?t???st??? t?? p2p s?st?µ?t?? (large scale,
  churn, zero-cost identity, collusions etc.)
• S?????s? t?? ap?te?esµ?t?? t??? µe ???µ??a p?s?
  s??e?sf????? st?? ap? ?????? ???s? p???? ???a ?a?
  p?? ep??e????? t?? ap?d?t???t?ta t?? s?st?µat??.
• ?????t? ??µata p??? ??e??a.