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
Questions / Conclusion ? ? ? ? ?