GNUTELLA PEER-TO-PEER NETWORKING

GNUTELLA n What is Gnutella n Relation to the World Wide Web n How it Works n Sites / Links / Information

WHAT IS GNUTELLA n Protocol that allows for peer-to-peer networking/communicating n Decentralized applications, were each user can act as a server n General public network, and private networks in isolation or attached to the public ones n Enables transient computers to effectively participate as servers DEFINITION

WHAT IS GNUTELLA n Search for information anonymously (you control what you look for) n Allows user to determine what information they wish to make public n Can choose what information to share –share nothing –one file –a directory –or your entire hard drive

WHAT IS GNUTELLA n First created by Nullsoft (developers of Winamp) n Protocol developed by them in 1999 n Many developers have created compatible code n Gnutella network exists only to the extent that these developed programs are running and communicating with one another CREATION

RELATION TO THE WWW n Gnutella hosts are web sites (although transient, equivalent to fetching a file from a web site) n Allows for P2P file sharing, but file transfer is accomplished via HTTP (the same protocol as web browsers and severs) n Each Gnutella application contains a web server component for serving files and a primitive browser element for retrieving them

RELATION TO THE WWW n WWW uses hyperlinks, under the assumption that content remains accessible under a fixed URL and server n Some computers/servers at a given IP address may not be the same, day-to-day, hour-to-hour, minute-to-minute, therefore they are transient TRANSIENT WEB

RELATION TO THE WWW n Augments HTTP with additional means to locate transient web sites n Traditional search engines cant find transient web sites n Decentralized, so no single responsible company, no central server, and no single point of failure n Anonymous searching (hosts are random users, not dedicated servers / search engines) ADVANTAGES

RELATION TO THE WWW n Distribution / searching is free, no promo’s. n Provides “superdistribution” users who download content can easily become re- distributors. ADVANTAGES

RELATION TO THE WWW n Search capability, no guarantee your query will reach the sites/users holding what you seek n Search results are unorganized n Puts PC end-user data at risk of unauthorized or unintentionally authorized exposure. n Cascading effect once files are shared or made available, others can redistribute them n Individual nodes/users can become overloaded since broadcasting info (scaling) DISADVANTAGES

HOW IT WORKS n You can be a fully functional Gnutella site by installing any of several available clients: WINDOWS Gnucleus BearShare Morpheus Swapper XoloX LimeWire Phex UNIX Gnewtellium Gtk-Gnutella Mutella Qtella LimeWire Phex MACINTOSH LimeWire Phex CONNECTING

HOW IT WORKS n Get connected to WWW n Next you have to find a few sites that are willing to communicate with you: –some may be friends –others may be advertised Gnutella sites CONNECTING

Searching by flooding: n If you don’t have the file you want, query 7 of your partners. n If they don’t have it, they contact 7 of their partners, for a maximum hop count of 10. n Requests are flooded, but there is no tree structure. n No looping but packets may be received twice. n Reverse path forwarding(?) n Gnutella Demo: Note: Play gnutella animation at: HOW IT WORKS

HOW IT WORKS (Gnucleus)

HOW IT WORKS n use key words only n do not use astriks, wild cards, dashes, commas, or periods n search results are immediate n processed by everyone connected n new connections made while searching will also be searched and results added n no re-search function needed SEARCHING

GNUTELLA: QUERY Query Query Hit

SITES / LINKS ADDRESSES FAQ’s

GNUTELLA & FREENET n Freenet: –bandwidth and disk space sharing concept for promoting free speech –very large & geographically distributed hard drive with anonymous access –Each file is assigned a complex unique identification –To search for files, need to search via that unique identification code n Gnutella: –Searching and discovery network promoting free interpretation and response to queries –Gnutella nodes to give hits in the form of filenames, advertising messages, URLs, graphics, and other arbitrary content

CONCLUSIONS n The key challenge of building wide area P2P systems is a scalable and robust location service –Naptser: centralized location service –*Gnutella : broadcast-based decentralized location service –*Freenet : intelligent-routing decentralized solution (but correctness not guaranteed; queries for existing items may fail)

REFERENCES n Gnutella – n Freenet – –Freenet: A Distributed Anonymous Information Storage and Retrieval System, Ian Clarke, Brandon Wiley, Oskar Sandberg and Theodore W. Hong\ – – –P2P Dynamic Networks –