what-when-how
In Depth Tutorials and Information
Chapter 6
UnderstandingInteractions
amongBitTorrentPeers
Haiyang Wang, Li Ma, Cameron
Dale, and Jiangchuan Liu
Contents
6.1
An Overview of BitTorrent.......................................................................128
6.1.1
Basic Operations of BitTorrent......................................................129
6.1.2
he Rarest-First Policy ..................................................................129
6.1.3
he Incentive Mechanism.............................................................130
6.1.4
Networks in the Torrents ..............................................................130
6.2
Data Exchange among Peers: he Piece-Level Examination..................... 131
6.2.1
Distribution of Piece Population...................................................132
6.2.1.1 Evolution of Piece Population .........................................133
6.2.1.2 he Feisty Torrents .........................................................134
6.2.1.3 Observation from Simulated PlanetLab Torrents............135
6.2.1.4 he PlanetLab-1 Torrent.................................................137
6.3
Neighbor Selection and Network Topologies: he Intra-Torrent Level
Examination.............................................................................................139
6.3.1
Background of Random Graphs ................................................... 141
6.3.2
Existence of Scale-Free Networks .................................................142
6.3.3
Small-World Networks: Negative Results ..................................... 145
6.3.3.1 Connectivity Matrix ....................................................... 150
6.3.3.2 Impact of Churn............................................................. 151
6.3.4
Possible Small-World Enhancement .............................................. 156
127
