b hierarchicalp2p hierarchicalp2pskype

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Unformatted text preview: y'seen'messages'are'not' further'forwarded' •  new'version'of'gnutella'uses' KaZaA7like'supernodes' B A query queryHit xyz.mp3( xyz.mp3(?( B Hierarchical'P2P' Hierarchical'P2P:'Skype' FastTrack'used'by'KaZaA,'Groskster,'iMesh,'Morpheus' Skype'forms'a'hierarchical'P2P:' •  hierarchical'architecture' •  peers'divided'into'supernodes'' and'ordinary'nodes' •  each'supernode'keeps'an'index'' of'all'its'children’s'files' •  requests'are'sent'to'supernodes' •  supernodes'query'each'other'for'' files'not'in'their'local'indices' •  index'mapping'usernames'to' •  searches'for'Skype'users' are'sent'to'supernodes' reg for'users'not'in'their'local'index' •  supernodes'choose'a'peer'to'act' as'relay'for'two'NATted'users' to'supernodes'if'they'have'enough'resources' and'have'stayed'on'network'long'enough' •  parallel'download'of'files' A! eDonkey/eMule'also'builds'a' hierarchical'network,'but'the'“supernodes”'are' dedicated'servers,'not'just'more'equal'peers' BitTorrent' Freenet:'Anonymous'P2P' •  requester'doesn’t'connect' open'host' •  supernodes'query'each'other' •  ordinary'nodes'are'“promoted”' •  no'index'server' B! IP'addresses'is'distributed' across'supernodes' req Peer-to-Peer Networking Content'distribution:' c = Data request = Data reply directly'to'content'provider' Requester 23 1 a b = Request failed 12 •  instead,'content'is'passed' in'a'bucket7brigade'fashion' d Data holder 4 7 11 10 6 from'provider'to'requester' 9 •  the'next'time'content'is' e 5 8 f requested,'it'is'provided' Figure 1.Typical request sequence.The request moves through the from'the'nearest'cache' network from node to node, backing out of a dead-end (step 3)...
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