Transcript Peer-to-Peer networking over the internet

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
Napster
 Gnutella
 Freenet
 KaZaA
 Morpheus
 LimeWire
 BearShare

Napster
Napster (con’t)
 Brief
History
 How Napster works:
 Central Server (stores location).
 Peers store files
 Is Napster a true P2P?
Gnutella
Gnutella (con’t)
 Brief
History
 How Gnutella works (uses TTL) :
 No central server
 Equal peers - (clients + server
roles)
 Gnutella - a true P2P
 Anonymosities
Gnutella (con’t)
LimeWire (Latest Technology)
Fastest File Sharing Program
 Gnutella – based application.
 Open standard software running on
an open protocol
 Allows 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 History
 How Freenet works
 No central server
 Equal peers - (clients + server roles)
 Inserting resources
 Search Termination
 Anonymous – secure network

Kazaa
Popular protocols
Fastrack (latest)
 Morpheus / Bearshare / Gnutella
 Gnutella 2
 Kazaa
 eDonkey
 DC++ (directConnect)
 Bittorent

FastTrack protocol
Used by KaZaA and Morpheus
 Supernodes and nodes
 Scalable
 Routing
 Routing Replies
 Routing Problems
 Partial 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 links
 Searches by flooding queries
 Disadvantage (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/dtucker
 www.google.com
 www.howstuffworks.com
 www.napster.com
 www.kazaa.com
 www.gnutella.com
 www.limewire.com

Questions / Conclusion
?
? ?
?
?
? ?