2/15/2001O'Reilly P2P Conference Characterizing P2P Infrastructure Wesley Felter Editor, Hack the...
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2/15/2001 O'Reilly P2P Conference Characterizing P2P Infrastructure Wesley Felter Editor, Hack the Planet http://felter.org/wesley/ [email protected]
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Transcript of 2/15/2001O'Reilly P2P Conference Characterizing P2P Infrastructure Wesley Felter Editor, Hack the...
2/15/2001 O'Reilly P2P Conference
Characterizing P2P Infrastructure
Wesley FelterEditor, Hack the Planethttp://felter.org/wesley/[email protected]
2/15/2001 O'Reilly P2P Conference
Overview
Choices common to many P2P systems Locations vs. Names App-Level vs. Network Routing Indexing vs. Wandering Specialization
File-sharing specific Whole Files vs. Blocks
Common Ground?
2/15/2001 O'Reilly P2P Conference
Locations vs. Names
Applies to peers, data, servicesLocations = URLs, Names = URNsLocations are simpler, faster, but inhibit replication Used by Napster, Gnutella
Names require directory service and namespace management Used by Freenet, Mojo Nation
2/15/2001 O'Reilly P2P Conference
Network vs. App-level routing
Network routing is “free”, minimizes latency Used by Napster, Mojo Nation
App-level routing can optimize for different metrics (e.g. privacy), provide multicast and replication Used by Freenet, OceanStore
Hybrids can work Gnutella routes queries, but sends data direct
2/15/2001 O'Reilly P2P Conference
Network Routing
2/15/2001 O'Reilly P2P Conference
Application-Level Routing
2/15/2001 O'Reilly P2P Conference
Application-Level Routing 2
2/15/2001 O'Reilly P2P Conference
Indexing vs. Wandering
Searching is used both for peers and data
Semi-centralized indices are efficient Used by Napster, Mojo Nation
Wandering (or flooding) requires queries to visit potentially many peers Used by Gnutella, Freenet, OceanStore
2/15/2001 O'Reilly P2P Conference
Specialization
All peers can perform exactly the same services Freenet
Or peers can specialize Simple case: Sharing or not More sophisticated: Gnutella Reflector,
Mojo Nation index “trackers”
2/15/2001 O'Reilly P2P Conference
Whole files vs. Blocks
Transferring whole files is simple, but resuming downloads becomes tricky Napster, Gnutella, Freenet
Breaking files into blocks increases overhead, but allows swarming & easier resuming Mojo Nation, OceanStore, Swarmcast
2/15/2001 O'Reilly P2P Conference
Is there a common ground?
Naming SHA-1 is already popular
Messaging HTTP and XML protocols
Directories
2/15/2001 O'Reilly P2P Conference
Questions?
Wesley Felter
http://felter.org/wesley/
