A survey of BitTorrent study

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A survey of BitTorrent study

• Jian Liang
• EL933
• Prof. Yong Liu

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Surveyed paper

• Service Capacity of Peer to Peer Networks
  (INFOCOM 2004) X. Yang, G. Veciana
• Modeling and Performance Analysis of Bit
  Torrent-Like Peer-to-Peer Networks (SIGCOMM 04)
  D. Qiu, R. Srikant
• The Bittorrent P2P File-sharing System
  Measurements and Analysis (IPTPS 2005) J.
  Pouwelse, P.Garbacki, D. Epema, H. Sips
• Measurements, Analysis, and Modeling of
  BitTorrent-like Systems (IMC 2005) L. Guo, S.
  Chen, Z. Xiao, E. Tan, X. Ding, and X. Zhang
• Analyzing and Improving BitTorrent Performance
  (INFOCOM 2006) A. Bharambe, C. Herley and V
  Padmanabhan

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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument
• Current development of BitTorrent

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Overview system components
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Overview system components
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Overview system components
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Overview system components
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Overview system components
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Overview system components
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Overview system components
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Overview BT features

• Temporal one torrent community (no across
  torrents communication).
• File/pieces/blocks. Content trade is piece based,
  while transfer is block based. Partial pieces can
  not be uploaded.

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Overview BT features

• Peer selection- Fit-for-Tat (download speed
  based) Interest/chock/unchock
• Piece selection - Local Rarest First (not global
  rarest)

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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument
• Current development of BitTorrent

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Research focus

• Generic network performance
• Traffic volume, download/upload throughput,
  uplink utilization, peer behavior, service
  capacity,
• Incentives
• Fairness, peer game
• Robustness
• Website availability, peer workload, content
  integrity.
• Limitation and improvement

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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument of their works
• Current development of BitTorrent

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Methodology

• Passive ways
• (tracker log, torrent website monitor, traffic
  capture)
• Active ways
• Join the BT network to monitor peer performance
• Simulation
• Modeling

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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument of their works
• Current development of BitTorrent

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Compare of these five works
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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument
• Current development of BitTorrent

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Interesting results

• YV_INFOCOM04
• Exponential growth of service capacity in initial
  flash crowd
• For less popular torrent (performance is quite unpredictable

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Interesting results

• QS_SIGCOMM04
• Purpose a good BT fluid model and matches their
  simulation result well.
• No surprising results yet.

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Interesting results

• PG_IPTPS05
• The arrival processes of peers are not Poisson
  assumed by SIGCOMM04 paper.
• Power law relationship btw peer speed and peers

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Interesting results

• PG_IPTPS05
• The availability of centralized supporting system
  is bad
• of seeds after 10 days is not accurate
  predictor for content life time, one single seed
  can be up for long period of time.

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Interesting results

• PGES_IPTPS05
• Centralized moderation seems very effective in
  removing fake and corrupted files. 5k of 8k
  torrent uploaded by 20 moderators daily.
• Donated resource for meta-data entail integrity
  and privacy risks without control.

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Interesting results

• GCXTDZ_IMC05
• Exponentially decreasing peer arrival rate, lack
  of seeds make service availability poor quickly
  after flash crowd.
• The leecher download speed at different time
  stages is highly diverse.

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Interesting results

• GCXTDZ_IMC05
• BT can provide unfair services. Peer contribution
  ratio decrease with its downloading speed
  increase.
• The probability for a peer to abort downloading
  voluntarily is independent of its speed and
  downloading progress.

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Interesting results

• GCXTDZ_IMC05
• The life spans of torrent is btw 30-300 hours
  with average 8.5 days average population of a
  torrent is only about 102 peers.
• Seeding time is average as 8.42 hours

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Interesting results

• BHP_INFOCOM06
• The uplink utilization close to 100
• Workload of seeds increase slowly during flash
  crowd

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Interesting results

• BHP_INFOCOM06
• Single seed utilization outperforms that of
  multi-seeds
• The more concurrent upload, the less uplink
  utilization

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Interesting results

• BHP_INFOCOM06
• For low bandwidth peers with small neighbors,
  random block exchange outperform LRF
• But LRF outperform random block exchange in term
  of interesting connections

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Interesting results

• BHP_INFOCOM06
• Block-level TFT outperform download speed based
  TFT in term of fairness
• Quick BW estimation help archive optimal
  utilization

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Interesting results

• BHP_INFOCOM06
• Bandwidth-matching tracker policy further improve
  both utilization and fairness

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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument
• Current development of BitTorrent

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Argument

• INFOCOM06
• the simulation does not consider user control of
  their uplink/downlink (BitComet enable uplink
  speed limits)
• Tradeoff of the improvement ideas
• Bandwidth measure overhead is ignored
• Bandwidth clustering helps but is that violation
  of Internet ethics by separating different
  capable users?

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Outline

• Overview of BitTorrent
• Research interests covered
• Methodology on BT study
• Compare of these 5 papers
• Interesting facts reflected in these works
• Argument
• Current development of BitTorrent

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Current BT development

• DHT enabled peer search (BitComet, Bitsprite)
• Decentralized torrent search (eXeem)
• BT like Content delivery system (VOD, IPTV)