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按一下以編輯母片標題樣式,按一下以編輯母片,第二層,第三層,第四層,第五層,*,*,*,Incentives Build Robustness in BitTorrent?,Analysis on Bit Torrent Client performance,By Jimmy Wong,1,Incentives Build Robustness in,Agenda,Introduction,BitTorrent Basics,Bit Tyrant:A strategic client,Bit Thief:A free-riding client,Other Tricks of BT Client,Real World Experiments,Avoiding of Tricks,Conclusion,2,AgendaIntroduction2,Introduction,BitTorrent core incentive,Upload More,Download More,Problem Definition,I am a selfish user,Can I gain without pay/pay less?,3,IntroductionBitTorrent core in,BitTorrent Basics,Step 0 Publishing Content,Create Torrent file,Tracker URL,SHA-1 Hash Checksum,Assign a Tracker,Distribute Torrent to users through Web Site,Newsgroup or Forum,4,BitTorrent BasicsStep 0 Publ,BitTorrent Basics,Step 1 Joining,Peers get the Torrent,Connect to Tracker,Look for available peers,DHT(Distributed Hash Table),Create connection with other peers,Start with Others Optimistic Unchoking,Look for better peers,Let other peers join the swarm,5,BitTorrent BasicsStep 1 Join,BitTorrent Basics,Step 2 to N-1 Pipelining,Exchange bitmap about which chunks are available,Pay more,get more,To build incentive for peers to upload,Reciprocal,Rarest first,To preserve File completeness among the swarm,To build up peers reputation,6,BitTorrent BasicsStep 2 to N-1,BitTorrent Basics,Choking,Send data to only few good peers,Contribute data to you,Have pieces that you wants,A resourceful peers,It will be nice if I can pay minimal cost to be un-choke!,7,BitTorrent BasicsChoking7,BitTorrent Basics,Optimistic Un-choking,Allow new peers to get some pieces for exchange,Allow discovery of better exchanging partners,Most peers are so friendly,I can gain without contribute!,8,BitTorrent BasicsOptimistic Un,BitTorrent Basics,Ending Phase,Toward the end of download,Request for missing pieces,Search for available peers,20-30 pieces left,9,BitTorrent BasicsEnding Phase9,Bit Tyrant:A strategic client,Incentive,100KB/s,15KB/s,1%drop,15KB/s,10KB/s,40%drop,About 1.9Mbps World Wide Bandwidth,http:/ do I still need to give u so much?,10,Bit Tyrant:A strategic client,Bit Tyrant:A strategic client,Resource Management,Bandwidth fixed,#Conn x Speed=Constant,Current Official BT Protocol(#of Leecher,Even better,Gain from both methodology,17,BitThief:A free-riding clien,Other Tricks of BT Client,Client Discrimination,Higher priority for Similar Client,Delibrately choke other client,Pretend to be Local Neighbor,Fake tracker with wrong upload rate,Retrieve from Seed,Rapid Disconnect and Reconnect,Hope to gain from optimistic unchoking,Remove from black-list,Multiple Connection to the same client,For high speed BB,Gain the most from the same client,18,Other Tricks of BT ClientClien,Experiment with BT Client,Testing Environment,Athlon 64 2800+,1GB Ram,120GB 7200 rpm HDD,Windows XP SP2 w/TCP Conn Crack,BT Software,Utorrent/Mainline,Bit Comet,Bit Tryant,iCable internet Connection,19,Experiment with BT ClientTesti,Experiment with BT Client,Gentoo AMD 64 Minimal ISO,54.4MB,34 Seeders,0 Leechers,Ubuntu 7.10 i386 Desktop ISO,695MB,928 Seeders/78 Leechers,NBA Match,921MB,120 Seeders,714 Leechers,20,Experiment with BT ClientGento,Experiment with BT Client,Gentoo,Upload,Time,Avg Speed,KB/s,Conn Peer,Seed/Leech,Bit Comet,0,18:40,50.65,10/0,uTorrent,0,17:01,55.62,12/0,Bit Tyrant,0,15:04,62.75,16/0,21,Experiment with BT ClientGento,Experiment with BT Client,Ubuntu,Upload,Time,Avg Speed,KB/s,Conn Peer,Seed/Leech,Bit Comet,32MB,15:20,773.57,75/70,uTorrent,112KB,69:13,171.37,36/1,Bit Tyrant,100KB,26:28,448.16,40/1,22,Experiment with BT ClientUbunt,Experiment with BT Client,NBA,Upload,Time,Avg Speed,KB/s,Conn Peer,Seed/Leech,Bit Comet,1070MB,52:32,299,11/53,uTorrent,1035MB,1:42:50,152,7/29,Bit Tyrant,540MB,1:20:10,196,10/22,23,Experiment with BT ClientNBAUp,Experiment with BT Client,Bit Thief,Achieve a high download rate(150KB/s)for Ubuntu and NBA,Suck at 25%,24,Experiment with BT ClientBit T,Avoiding Tricks,Target,Stop Fake Information,Identify Free-riding,Difficulties,Bit Torrent is so wide spread,Too many implementations,Incentive driven works again!,Co-operative identify bad client,Block bad peers,Share with good peers,25,Avoiding TricksTarget25,Avoiding Tricks,Sharing with Peers,Search for local optimal best peers,Search for potential bad peers,Broadcast of bad peers(In a majority basics),It will fail if more than half of clients are in-honest,26,Avoiding TricksSharing with Pe,Conclusion,BT Robustness,Most peers are friendly,Ways to Crack,Gain from cracking the protocol,Bit Tyrant:Download Upload,Bit Thief:Free Riding,Proposed Solution,Decentralized Client Solution,27,ConclusionBT Robustness27,Reference,Incentives Build Robustness in BitTorrent,http:/www.bittorrent.org/bittorrentecon.pdf,Do incentives build robustness in BitTorrent?,http:/www.cs.washington.edu/homes/piatek/papers/BitTyrant.pdf,Free Riding in BitTorrent is Cheap,http:/dcg.ethz.ch/publications/hotnets06.pdf,28,ReferenceIncentives Build Robu,
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