A survey of BitTorrent study


1
A survey of BitTorrent study

• Jian Liang
• EL933
• Prof. Yong Liu

2
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

3
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

4
Overview system components
5
Overview system components
6
Overview system components
7
Overview system components
8
Overview system components
9
Overview system components
10
Overview system components
11
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)

13
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

14
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

15
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

16
Methodology

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

17
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

18
Compare of these five works
19
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

20
Interesting results

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

21
Interesting results

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

22
Interesting results

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

23
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.

24
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.

25
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.

27
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

30
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

31
Interesting results

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

32
Interesting results

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

33
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

34
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

36
Current BT development

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