Fast Download but Eternal Seeding: The Reward and Punishment of Sharing Ratio Enforcement

AL Jia, R Rahman, T Vinko, JA Pouwelse, DHJ Epema

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

21 Citations (Scopus)
15 Downloads (Pure)


Many private BitTorrent communities employ Sharing Ratio Enforcement (SRE) schemes to incentivize users to contribute their upload resources. It has been demonstrated that communities that use SRE are greatly oversupplied, i.e., they have much higher seeder-to-leecher ratios than communities in which SRE is not employed. The first order effect of oversupply under SRE is a positive increase in the average downloading speed. However, users are forced to seed for extremely long times to maintain adequate sharing ratios to be able to start new downloads. In this paper, we propose a fluid model to study the effects of oversupply under SRE, which predicts the average downloading speed, the average seeding time, and the average upload capacity utilization for users in communities that employ SRE. We notice that the phenomenon of oversupply has two undesired negative effects: a) Peers are forced to seed for long times, even though their seeding efforts are often not very productive (in terms of low upload capacity utilization); and b) SRE discriminates against peers with low bandwidth capacities and forces them to seed for longer durations than peers with high capacities. To alleviate these problems, we propose four different strategies for SRE, which have been inspired by ideas in social sciences and economics. We evaluate these strategies through simulations. Our results indicate that these new strategies release users from needlessly long seeding durations, while also being fair towards peers with low capacities and maintaining high system-wide downloading speeds.
Original languageEnglish
Title of host publication2011 IEEE International Conference on Peer-to-Peer Computing (P2P11)
EditorsT Asami, T Higashino, A Ghodsi
Place of PublicationPiscataway, NJ
PublisherIEEE Society
Number of pages10
ISBN (Print)978-1-4577-0149-8
Publication statusPublished - 2011
EventP2P11 - Piscataway, NJ, USA
Duration: 31 Aug 20112 Sep 2011




  • Communities
  • Steady-state
  • Peer to peer computing
  • Bandwidth
  • IEEE Communications Society
  • Analytical models
  • Thin film transistors

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    Jia, AL., Rahman, R., Vinko, T., Pouwelse, JA., & Epema, DHJ. (2011). Fast Download but Eternal Seeding: The Reward and Punishment of Sharing Ratio Enforcement. In T. Asami, T. Higashino, & A. Ghodsi (Eds.), 2011 IEEE International Conference on Peer-to-Peer Computing (P2P11) (pp. 280-289). IEEE Society.