Modeling Analysis and Improvement for Free-Riding on BitTorrent-like File Sharing Systems

BitTorrent has emerged as a very popular peer-to- peer file sharing system, which uses an embedded set of incentive mechanisms to encourage contribution and prevent free-riding. However, the capability BitTorrent has of preventing free-riding needs further study. In this paper, we present a fluid model with two different classes of peers to capture the effect of free-riding on BitTorrent-like systems. With the model, we find that BitTorrent's incentive mechanism is successful in preventing free-riding in a system without seeds, but may not succeed in producing a disincentive for free-riding in a system with a high number of seeds. The reason for this is that BitTorrent does not employ an effective mechanisms for seeds to effectively guard against free-riding. Therefore, we propose a seed bandwidth allocation strategy for the BitTorrent system to reduce the effect of seeds on free-riding. Finally, simulation results are given, which validate what we have found in our analysis and demonstrate the effectiveness of the proposed strategy.

[1]  Keith W. Ross,et al.  Multiclass P2P networks: Static resource allocation for service differentiation and bandwidth diversity , 2005, Perform. Evaluation.

[2]  Mao Yang,et al.  An Empirical Study of Free-Riding Behavior in the Maze P2P File-Sharing System , 2005, IPTPS.

[3]  Frank Kelly,et al.  Mathematical Modelling of the Internet , 2001 .

[4]  Francesca Lo Piccolo,et al.  The effect of heterogeneous link capacities in BitTorrent-like file sharing systems , 2004, 2004 International Workshop on Hot Topics in Peer-to-Peer Systems.

[5]  M. Omizo,et al.  Modeling , 1983, Encyclopedic Dictionary of Archaeology.

[6]  Christos H. Papadimitriou,et al.  Free-riding and whitewashing in peer-to-peer systems , 2004, IEEE Journal on Selected Areas in Communications.

[7]  B. Cohen,et al.  Incentives Build Robustness in Bit-Torrent , 2003 .

[8]  Mikel Izal,et al.  Dissecting BitTorrent: Five Months in a Torrent's Lifetime , 2004, PAM.

[9]  Mustaque Ahamad,et al.  Incentives in BitTorrent induce free riding , 2005, P2PECON '05.

[10]  Johan A. Pouwelse,et al.  The Bittorrent P2P File-Sharing System: Measurements and Analysis , 2005, IPTPS.

[11]  Xiaoning Ding,et al.  Measurements, analysis, and modeling of BitTorrent-like systems , 2005, IMC '05.

[12]  Eytan Adar,et al.  Free Riding on Gnutella , 2000, First Monday.

[13]  Chua-Huang Huang,et al.  2003 International Conference on Parallel Processing Workshops , 2003 .

[14]  Stefan Saroiu,et al.  A Measurement Study of Peer-to-Peer File Sharing Systems , 2001 .

[15]  Geoff Coulson,et al.  Free Riding on Gnutella Revisited: The Bell Tolls? , 2005, IEEE Distributed Syst. Online.

[16]  Gustavo de Veciana,et al.  Service capacity of peer to peer networks , 2004, IEEE INFOCOM 2004.

[17]  Rayadurgam Srikant,et al.  Modeling and performance analysis of BitTorrent-like peer-to-peer networks , 2004, SIGCOMM 2004.

[18]  Venkata N. Padmanabhan,et al.  Analyzing and Improving BitTorrent Performance , 2005 .

[19]  Dimitri P. Bertsekas,et al.  Data Networks , 1986 .

[20]  Kam-Wing Ng,et al.  Modeling, Analysis and Improvement for BitTorrent-Like File Sharing Networks , 2006, Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications.