Transcript Peer-to-Peer network systems

Peer-to-Peer
network systems
Distributed Data Processing
Paulina Pasek
Content
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Introduction
How does internet p2p work?
History
Advantages
Disadvantages
Legal controversy
Networks and their applications
Summary
Sources
Whata is peer-to-peer (p2p)?
1.
„(…) a type of network in which each work station has equivalent
capabilities and responsibilities”
source: webopedia.com
2.
"individual computers may share hard drives, CD-ROM drives,
and other storage devices with the other computers on the
network." Contrast with this, in a client/server set-up, "most of the
computers (clients) tend to share resources from one main
computer (the server). "
source: p2p.inf.pl
3.
Peer-to-peer is a communications model in which each party has
the same capabilities and either party can initiate a
communication session. Other models with which it might be
contrasted include the client/server model and the master/slave
model..."
source: searchNetworking .techtarget.com
File sharing – the differences
In FTP (File Transfer Protocol) and HTTP (HyperText Transfer Protocol)
must be some server, someone have to buy it and take care of it.
• Easy to find operator if on server are illegal files
• If many people know about it could be a problem with downloading
In p2p
• No servers (connecting directly to computer)
• Easy to upload something
• You don’t need money
• Nobody can permit the operator of the server cause there is no
server
• No problems with download speed (because there is no server)
Example of data sharing
How does internet p2p work?
• The user must first downlad and execute a peer-to-peer networking
program. After launching the program, the user enters the IP
address of another computer beloning to the network. Once the
computer finds another network member on-line, it will connect to
that user’s connection
• Users can choose how many member connections to seek at one
time and determine which files they wish to share or password
protect
History
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July, 1999: publication of Freenet protocol
September, 1999: creation of Napster
November, 1999: first release of Direct Connect client
March 14, 2000: first release of Gnutella
September 6, 2000: first release of eDonkey2000
March, 2001: introduction of the FastTrack protocol
April, 2001: design of the BitTorrent protocol
July, 2001: shutdown of Napster
November 6, 2001: first release of GNUnet
November, 2002: start of the Gnutella2 project
Advantages
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each user increases total capacity of the network
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low maintenance costs
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flexible structure (”liquid topology”)
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end of Internet asymmetry
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Almost free
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Fast dowlanding
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Very popular
Disadvantages
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Not so safe:
viruses, spam, spyware
downloaded files may be infected, contain unsolicited information,
violate privacy
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Sometimes illegal
copyrighted files within p2p networks
What should we be aware of?
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shared files as copies of copyrighted music, movies,
programs, e-books, etc…
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MPAA (Motion Picture Association), RIAA
(Recording Industry Association of America) – an
example of organizations fighting with piracy
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small loophole…
What are we allowed to
download?
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files with authors’ permission to download
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files without current copyrights
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(wallpapers, anime music videos)
(e.g. old programs, lot of remixes)
files with time-out copyrights
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(classical music, old e-books)
Networks and their clients
IRC
Napster
Gnutella
FastTrack
Freenet
Direct Connect
eDonkey
Skype
IRC
IRC (Internet Relay Chat) it’s not p2p network
Have a conversations is for help channels in
IRC net
DCC (Direct Client-to-Client)
The users use pseudonyms like nicname or
short nick
Napster
• the first p2p network
• created by Shawn Fanning (1999)
• Napster users can’t only play the music back after
downlading it but put it on their own CD.
• closed in 2001 (lost lawsuit), returned in 2003 as paid
service
• Logo:
Gnutella
• Gnutella lets users share files from user machine to user machine
without the use of a central directory
• In Gnutella don’t have a central server
• Files are changing between users
• You are connecting directly to host without any servers
• The first program was written by Justin Frankl and Tom Pepper
• Name of Gnutella is compound words GNU and Nutella
• Adwantages: biggest no. of clients
no queue
a lot of files avaliable
• Logo:
BitTorrent
• Written by San Francisco programmer Bram Cohen in 2002
• BitTorrent is similar to KaZaA and other distributed swapping
services
• users download from other users and do not use a centralized
directory as in the original Napster service
• BitTorrent is also different than all of them because it makes every
downloading user an uploading user
• Logo:
eDonkey
• p2p file sharing application developed by MetaMachine
• Like most file sharing networks, it is decentralized
• files are not stored on a central server but are exchanged directly
between users based on the p2p principle.
• Advantages: lot of files
very good queue
biggest network
• Logo:
FastTrack
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P2p protocal used by the Kazaa file sharing programs
In 2003 it was the most popular file sharing network
The network had approximately 2.4 million concurrent users in 2003
the brainchild of Niklas Zennstrom, Janus Friis and Estonian
programmers headed by Jaan Tallinn, the same team that later
created Skype
• Most famous clients: iMesh*, Mammoth, Kazaa, Kazaa Lite, Diet
Kazaa
• Advantages: good from technical point of view
lot of take files
• Logo:
Direct Connet
• P2P file sharing application written by NeoModus
• today is the general type of application used in a Direct Connect
network
• Direct connect clients connect to a central hub and can download
files directly from one another
• Hubs feature a list of clients or users connected to them. Users can
search for files and download them from other clients, as well as
chat with other users.
• Logo:
Skype
• It was created by Niklas Zennström, Janus Friis, and a team of
software developers based in Tallinn, Estonia
• Instant messaging based on p2p
• Conferences
• Connect directly to user
• Possibility exchange files
• Chat
• Logo:
How does it look?
Summary
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Very useful, very flexible
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Very popular
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P2P as alternative to FTP and HTTP
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Fast downlading
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Not so save
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Almost free
Sources
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www.wikipedia.pl
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www.webopedia.com
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http://www.fact-index.com/p/pe/peer_to_peer.html
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http://www.p2p.info.pl
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http://www.fact-index.com
Thank you
For your attention