peer to peer (p2p) network

PEER TO PEER (P2P) NETWORK

By:

Linda Rockson

11/28/06

Outline:

Definition of Peer-to-Peer (P2P) P2P technologies LimeWire (Latest Technology) How LimeWire works Protocol survey Structured and Unstructured P2P Difference between P2P and server based The future of P2P References and Conclusion

Definition of P2P

A peer-to-peer (P2P) network is one that relies primarily on the resources of the participants in the network rather than on a server

(wikipedia)

P2P Technologies

NapsterGnutellaFreenetKaZaAMorpheusLimeWireBearShare

Napster

Napster (con’t)

Brief HistoryHow Napster works:Central Server (stores location).Peers store filesIs Napster a true P2P?

Gnutella

Gnutella (con’t)

Brief HistoryHow Gnutella works (uses TTL) :No central serverEqual peers - (clients + server

roles)Gnutella - a true P2PAnonymosities

Gnutella (con’t)

LimeWire (Latest Technology)

Fastest File Sharing ProgramGnutella – based application. Open standard software running on

an open protocolAllows file-sharing

for .mp3, .jpg, .tiff, Written in Java.Runs on Windows, Mac, Linux, Sun

How LimeWire works

How LimeWire works (con’t)

Node A1 is first connected to the network.

Pings to Nodes (B and C) to find new nodes on the network.

Pong message(node, IP, port No, No files shared)

Sends a query for files shared by other nodes.

Reply (file(s), size, link speed of the node)

Downloads required file for play/use

Freenet

Brief HistoryHow Freenet worksNo central serverEqual peers - (clients + server roles)Inserting resourcesSearch TerminationAnonymous – secure network

Kazaa

Popular protocols

Fastrack (latest)Morpheus / Bearshare / GnutellaGnutella 2KazaaeDonkeyDC++ (directConnect)Bittorent

FastTrack protocol

Used by KaZaA and MorpheusSupernodes and nodes Scalable Routing Routing RepliesRouting ProblemsPartial Decentralisation

P2P Protocols Problem

Problem: Creates traffic (act server + client)

Solution ET/BWMGR software "sniff out" protocols Controls or block traffic Completely disallows communication Finds protocols irrespective of port used

(80)

Structured and Unstructured P2P

Basis – nodes linkage in the network

Unstructured:Easily constructed: copy existing linksSearches by flooding queriesDisadvantage (unresolved queries)Eg: Napster, Gnutella, KaZaA

Structured P2P

Maintains a Distributed Hash Table (DHT)

Peer responsibility

Searches with hash function

More efficient

Egs: Chord, Tapestry, CAN, Tulip

Advantages of P2P over server based

Inexpensive high scability

Network growth increases resources

No centralized systems – hence cheap

1 program on multiple machines at once

Server: traffic, goes down, resources

Future of Peer-to-Peer

Lack of scalability.

Trust (resources) in the network

Virus control

It must be robust (logout leads to difficult download)

References

users.edinboro.edu/dtuckerwww.google.comwww.howstuffworks.comwww.napster.comwww.kazaa.comwww.gnutella.comwww.limewire.com

Questions / Conclusion

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