Gnutella

Key takeaways

Gnutella belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gnutella to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gnutella from memory before moving on to harder problems.

Reference excerpt

Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model. In June 2005, Gnutella's population was 1.81 million computers increasing to over three million nodes by January 2006. In late 2007, it was the most popular file-sharing network on the Internet with an estimated market share of more than 40%.

History The first client (also called Gnutella) from which the network got its name was developed by Justin Frankel and Tom Pepper of Nullsoft in early 2000, soon after the company's acquisition by AOL. On March 14, the program was made available for download on Nullsoft's servers. The event was prematurely announced on Slashdot, and thousands downloaded the program that day. The source code was to be released later, under the GNU General Public License (GPL); however, the original developers never got the chance to do this. The next day, AOL removed the program from its website over legal concerns and restrained Nullsoft from doing any further work on the project. This did not stop Gnutella; after a few days, the protocol had been reverse engineered, and compatible free and open source clones began to appear. This parallel development of different clients by different groups remains the modus operandi of Gnutella development today. Among the first independent Gnutella pioneers were Gene Kan and Spencer Kimball, who launched the first portal aimed to assemble the open-source community to work on Gnutella and also developed "GNUbile", one of the first open-source (GNU-GPL) programs to implement the Gnutella protocol. The Gnutella network is a fully distributed alternative to such semi-centralized systems as FastTrack (KaZaA) and the original Napster. The initial popularity of the network was spurred on by Napster's threatened legal demise in early 2001. This growing surge in popularity revealed the limits of the initial protocol's scalability. In early 2001, variations on the protocol (first implemented in proprietary and closed source clients) allowed an improvement in scalability. Instead of treating every user as client and server, some users were now treated as ultrapeers, routing search requests and responses for users connected to them. This allowed the network to grow in popularity. In late 2001, the Gnutella client LimeWire Basic became free and open source. In February 2002, Morpheus, a commercial file sharing group, abandoned its FastTrack-based peer-to-peer software and released a new client based on the free and open source Gnutella client Gnucleus. The word Gnutella today refers not to any one project or piece of software, but to the open protocol used by the various clients. The name is a portmanteau of GNU and Nutella, the brand name of an Italian hazelnut flavored spread: supposedly, Frankel and Pepper ate a lot of Nutella working on the original project, and intended to license their finished program under the GNU General Public License. Gnutella is not associated with the GNU project or GNU's own peer-to-peer network, GNUnet. On October 26, 2010, the popular Gnutella client LimeWire was ordered shut down by Judge Kimba Wood of the United States District Court for the Southern District of New York when she signed a Consent Decree to which recording industry plaintiffs and LimeWire had agreed. This event was the likely cause of a notable drop in the size of the network, because, while negotiating the injunction, LimeWire staff had inserted remote-disabling code into the software. As the injunction came into force, users who had installed affected versions (newer than 5.5.10) were cut off from the P2P network. Since LimeWire was free software, nothing had prevented the creation of forks that omitted the disabling code, as long as LimeWire trademarks were not used. The shutdown did not affect, for example, FrostWire, a fork of LimeWire created in 2004 that carries neither the remote-disabling code nor adware. On November 9, 2010, LimeWire was resurrected by a secret team of developers and named LimeWire Pirate Edition. It was based on LimeWire 5.6 BETA. This version had its server dependencies removed and all the PRO features enabled for free.

Design

… excerpt ends here. Continue reading the full article.

Illustrations

Gnutella: The gnutella search and retrieval protocol — The gnutella search and retrieval protocol

Worked examples

Example 1 — a first encounter with Gnutella

Start with the simplest possible case. Write down what Gnutella claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Gnutella before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Gnutella ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Gnutella

In research: Gnutella appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Gnutella in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Gnutella is common in secondary-school and first-year university syllabi. It links to neighbouring topics Application layer protocols, File sharing networks, Gnutella, so understanding it makes those chapters shorter.
In everyday life: Look for Gnutella outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Gnutella in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gnutella means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Gnutella out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gnutella in simple terms?

Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model.

Why does Gnutella matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Gnutella?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Gnutella.