Improving fairness in peer-to-peer networks by separating the role of seeders in network infrastructures

:Fairness is one of the most important challenges that should be considered as a priority when designing a P2P file-sharing network. An unfair P2P network may attract free-riders, frustrate the majority of users, and consequently shorten the longevity of files. When BitTorrent protocol was first introduced, by suggesting new algorithms like tit-fortat or rarest-first and combining them with methods like choking and unchoking, it pushed fairness one step forward. However, BitTorrent did not bring a plenary solution and has its own shortcomings. For instance, neither this protocol nor other P2P protocols that we are aware of precisely indicate how seeders should be treated in their networks. Most of the time they dictate that seeders upload as much as possible. With this approach, seeders can easily be abused by free-riders. It gets even worse when we realize that for lack of a good infrastructure a lawful user may become a free-rider unknowingly. The purpose of this paper is to address this problem by suggesting a novel and universal method that can be implemented in current P2P networks. We show that by separating nodes into two groups of seeders and leechers and then implementing a simple pattern for seeders, we can improve fairness in P2P networks. Even though our algorithm is universal and not limited to a specific protocol, by implementing it on BitTorrent we show how it can be used in practice and how effective it is.

PDF

___

[1] Buford J, Yu H. Peer-to-peer networking and applications: synopsis and research directions. In: Shen X, Yu H, Buford J, Akon M, editors. Handbook of Peer-to-Peer Networking. New York, NY, USA: Springer, 2010. pp. 3-45.
[2] Bondi A. Characteristics of scalability and their impact on performance. In: Workshop on Software and Performance; 2000. pp. 195-203.
[3] Napster Protocol. April 2000. Available from drscholl@users.sourceforge.net.
[4] Clip2 Distributed Search Services. Gnutella Protocol v04. Available from www.clip2.com.
[5] Adar E, Huberman B. Free riding on Gnutella. First Monday 2000; 5: 10.
[6] Hughes D, Coulson G, Walkerdine J. Free riding on Gnutella revisited: the bell tolls? IEEE Distributed Systems Online 2005; 6: 6.
[7] Cohen B. Incentives build robustness in BitTorrent. In: P2PEcon; 2003.
[8] Jun S, Ahamad M. Incentives in BitTorrent induce free riding. In: ACM SIGCOMM Workshop on Economics of Peer-to-Peer Systems; August 2005; Philadelphia, PA, USA. pp. 116-121.
[9] Liogkas N, Nelson R, Kohler E, Zhang L. Exploiting BitTorrent For fun (but not profit). In: 5th International Workshop on Peer-to-Peer Systems; February 2006; Santa Barbara, CA, USA.
[10] Locher T, Moor P, Schmid S, Wattenhofer R. Free riding in BitTorrent is cheap. In: 5th Workshop on Hot Topics in Networks; November 2006; Irvine, CA, USA.
[11] Piatek M, Isdal T, Anderson T, Krishnamurthy A, Venkataramani A. Do incentives build robustness in BitTorrent? In: 4th USENIX Conference on Networked Systems Design & Implementation; December 2006; Berkeley, CA, USA.
[12] Sirivianos M, Park J, Chen R, Yang X. Free-riding in BitTorrent networks with the large view exploit. In: IPTPS; 2007.
[13] Andrade N, Mowbray M, Lima A, Wagner G, Ripeanu M. Influences on cooperation in BitTorrent communities. In: ACM SIGCOMM Workshop on Economics of Peer-to-Peer Systems; 2005; New York, NY, USA. pp. 111-115.
[14] Sirivianos M, Yang J, Jarecki S. Dandelio: Cooperative content distribution with robust incentives. In: USENIX Annual Technical Conference; 2007. pp. 157-170.
[15] Izhak-Ratzin R, Liogkas N, Majumdar R. Team incentives in BitTorrent systems. In: 18th International Conference on Computer Communications and Networks. pp. 1-8.
[16] Izhak-Ratzin R. Improving the BitTorrent protocol using different incentive techniques. PhD, UCLA, Los Angeles, CA, USA, 2010.
[17] Shin K, Reeves D, Rhee I. Treat-before-trick: free-riding prevention for BitTorrent-like peer-to-peer networks. In: IPDPS; 2009; Rome, Italy. pp. 1-12.
[18] Lei Xia R, Muppala J. Discovering free-riders before trading: a simple approach. In: 16th International Conference on Parallel and Distributed Systems; 2010; China. pp. 806-811.
[19] Garbacki P, Epema D, Steen M. An amortized tit-for-tat protocol for exchanging bandwidth instead of content in P2P networks. In: Self-Adaptive and Self-Organizing Systems; 2007. pp. 119-128.
[20] Stoica I, Morris R, Liben-Nowell D, Karger D, Kaashoek MF, Dabek F, Balakrishnan H. Chord: a scalable peerto-peer lookup protocol for Internet applications. IEEE/ACM T Netw 2003; 11: 17-32.
[21] Jelasity M, Montresor A, Paolo G, Voulgaris S. PeerSim: A Peer-to-Peer Simulator. Available at https://sourceforge.net/.