Peer-to-Peer (P2P) Networks
By
Bongju Yu
Contents
What is P2P?
Features of P2P systems
P2P Architecture
P2P Protocols
P2P Projects
Reference
What is P2P ?
P2P is Peer-to-Peer.
Sharing of computer resources and services
by direct exchange between systems.
Resources including the exchange of
information, processing cycles, cache
storage, and disk storage for files.
Features of P2P systems
Distributed computing and resources
Collaboration
Intelligent agents
Core technologies
P2P Architecture
 Computers that have been used as clients
communicate directly among themselves
and can act as both clients and servers.
 Two basic models of P2P technology
 Server dependant
 True P2P
Server dependant
Considered as centralized since it holds a
catalog of addresses.
The addresses are referenced by a set of
indexes that determine the appropriate
address set.
A classic example : Napster
True P2P
This type has every node as a Peer, and
lacks a central router.
The routing structure either is a distributed
catalog which uses indexes as parameters or
direct messaging where the message is sent
to a peer group until the inquiry is found.
The popular example : Gnutella
P2P Protocols
Connection Establishment
Search and Download
TTL (Time To Live)
P2P Projects
Napster
Scour
Gnutella
Freenet
Napster
The most popular P2P file-sharing program.
Lacking many of the advanced features of
other P2P programs and limiting its file
sharing capabilities to MP3 files only.
The first to be hit by lawsuits, Napster is
still involved in legal battles.
Scour
Very popular with the second largest user
base.
Users could share files of type MP3, video,
and documents.
After the developments in Napster's case,
and facing impending court cases, decided
to shut down.
Gnutella
The first "true" P2P program.
Files of any type can be shared. To facilitate
file sharing, messages are sent between end
hosts.
Plagued with slow searches and a need for
high bandwidth connections.
Freenet
Cannot be detected what files a user has
downloaded or uploaded from the Freenet
network.
Employing intelligent routing techniques
superior to Gnutella.
If a user that was sharing files goes offline,
his files remain available to download.
Reference
1.
2.
3.
4.
Geoffrey Fox, “Peer-to-Peer Networks”, Computing in Science &
Engineering, Volume 3, Issue 3, Page 75 - 77, 2001.
Manoj Parameswaran, Anjana Susarla and Andrew B. Winston,
“P2P Networking: An Information-Sharing Alternative”, Computer,
Volume 34, Issue 7, Page 31 - 38, 2001.
Andy Oram, “Peer-To-Peer: Harnessing the Benefits of a Disruptive
Technology”, O’Reilly & Associates, Inc., 2001.
David Wiley, “Peer-to-Peer and Learning Objects: the New
Potential for Collaborative Constructivist Learning Online”,
Proceedings IEEE International Conference on Advanced Learning
Technologies, Page 494 - 495, 2001.
Thank you!
End