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Tribler Download Core Improvement. IN3700 Bachelor Thesis. Presentation by Rick van Hattem Raynor Vliegendhart. Committee Dr. Ir. J.A. Pouwelse Ir. B.R. Sodoyer. Overview. Introduction Problem Analysis Evolution of BitSMART (our measurement tool) Shortcomings of BitSMART
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Tribler Download Core Improvement IN3700 Bachelor Thesis Presentation by Rick van Hattem Raynor Vliegendhart Committee Dr. Ir. J.A. Pouwelse Ir. B.R. Sodoyer
Overview • Introduction • Problem Analysis • Evolution of BitSMART (our measurement tool) • Shortcomings of BitSMART • Acquired Insights • Project’s Delays • Demonstration • Conclusion and Future Work • Questions
Introduction (1) • Users want to share files • Peer-to-peer file sharing protocols • BitTorrent is popular BitTornado ABC Mainline Tribler BitComet Azureus et cetera… BitTyrant µTorrent
Introduction (2) • Sharing versus Leeching • BitTorrent incents users to share • Reward: performance • How does Tribler fare? • Measuring is knowing!
Problem Analysis • Performance Behaviour • So what is good sharing behaviour? • Depends on point of view of other peers • Upload bandwidth is scarce • Ergo: bandwidth = currency • Research the best strategy:Optimize the value of your upload bandwidth
Evolution of BitSMART (1) • Original project’s goal:Analysis and Implementation • Approach: Logging (next slide)
logging Evolution of BitSMART (2)
Evolution of BitSMART (3) • Disadvantages: • Not scalable • Limited applicability • Advantage: • All BitTorrent informationreadily available in memory
Evolution of BitSMART (4) • Project’s change:Focus on Analysis only • Approach: Network traffic analysis (next slide)
usual BT stack capture part Evolution of BitSMART (5)
Evolution of BitSMART (6) • Advantages: • Scalable • Can be applied to all clients • Disadvantages: • Considerable more effort to implement • Not 100% reliable,encrypted connections cannot be deciphered
Shortcomings of BitSMART (1) • Two possible alternative implementations: • PCAP (raw Ethernet frames) • PDML (XML format) • Choice: PDML format • Why? It seemed to be: • Easier • Less error prone • Less time to implement
Shortcomings of BitSMART (2) Unfortunately, the easy path was deceiving • Large PDML files:DOM readers not feasible • PDML missing details • Packets lost in translation,PCAP PDML
Shortcomings of BitSMART (3) Consequences: • Dealing with these drawbackscost a lot of time • Missing details madethe resulting toolless powerful
Shortcomings of BitSMART (4) • Choosing PCAP would have preventeda lot of problems • However, it would still have cost a lot of time to implement • Reason: Lots of low level tasks to be done
Acquired Insights (1) • Due to the limitations of the PDML format,analysis was not as in-depth as desired • Nevertheless, we acquired some interesting insights
Acquired Insights (2) • Attaining high download speeds as fast as possible • Finding and trying out peers is important
Acquired Insights (3) • Endgame mode’s purpose is to retain speed
Acquired Insights (4) • Explanation for Mainline’s bad performance:Peer discovery not aggressive
Acquired Insights (5) However, a later measurement surprised us: • Mainline was the fastest • Mainline found the least amount of peers Mainline Tribler
Acquired Insights (6) A possible explanation: • Mainline was lucky and immediately found good peers • Finding/Trying out peers costs time • If true, adaptive strategies are rewarding
Project’s Delays (1) • Original planning:Begin of May to begin of July • Progress went fine • Project’s change:Begin of June • Re-planning failed:New tasks heavily underestimated
Project’s Delays (2) • Underestimation caused by • Being optimistic • Trying to fit the new tasks in the remaining time • Underestimation was a source of delay • Due to the delay, other conflicting events increased the delay
Demonstration (1) A true live demonstration not possible, so we show a few preliminary steps on these slides.
Demonstration (2) • First, we start tshark
Demonstration (3) • Then, start the BitTorrent client to be measured • Start the download
Demonstration (4) • After the download, stop the BT client and tshark • Process the captured packets with BitSMART • Enjoy the live demonstration!
Conclusion and Future Work (1) • Tribler is one of the slowest BitTorrent clients • Main improvements in: • Peer discovery • Endgame mode • To be researched: • Adaptive strategies
Conclusion and Future Work (2) • BitSMART: • Tool is usable, but limited in power • PDML format is a dead-end • Effort should be spent in writing a PCAP analyser • Reason for further research: Measuring is knowing!