PEER-TO-PEER

A peer-to-peer (P2P) operation is where individuals within a niche market open their computers and allow others to upload files directly from their hard drives. Sharing music, video, and software are the most popular reasons for adopting a P2P business model, but there are many ways a P2P model can be used to enable a niche market to share information and files. For example, film students could share their creations, bird lovers could share photos, migratory information, etc., and software programmers find P2P networks invaluable when writing code.

There are a few different types of P2P networks. Let’s examine the most popular models.

Napster model. This refers to a centralized version of peer-to-peer file sharing that is designed around a central server that directs traffic between registered users. The central server maintains a directory of all registered user’s shared files (which are stored on each individual’s computer). To find a specific file, a registered user types in search criteria (e.g. name of song, artist, book title, genre, etc.) and starts a search of the system. The central server then retrieves a list of files matching the search request, which it presents to the requesting user. The user then selects the desired file(s) from the list and opens a direct link to the individual computer that contains the desired file(s) and downloads the file(s) directly from the other user’s computer. Actual files are never stored on the central server. The problem with this version of P2P networking is that if the central server goes down the entire network is unavailable to end-users.

Figure 23: The difference between a Napster-like network and a Gnutella-based network.

Gnutella model or decentralized network. This model originated from the Gnutella protocol written by Justin Frankel, the 21-year old founder of Nullsoft. It can be described as a type of call-and-response protocol, i.e. a more complicated email or news protocol.

Nullsoft posted Gnutella on the Web in March 1999. Then in June 1999 Nullsoft was acquired by America Online (AOL), and a day later AOL yanked Gnutella, but several thousand downloads had already occurred, allowing reverse engineering to take its course. Thus Gnutella continues today, albeit under the auspices of independent programmers who offer popular P2P software packages such as LimeWire, Kazaa and BearShare. These software packages and many more can access the same “Gnutella” P2P network — a network that does not use a central server to keep track of users’ files. Each instance of a Gnutella-type software acts as both a server and a client because the software supports bidirectional information transfer.

All you need to operate a fully functional Gnutella network is to install any of several available Gnutella software packages (Kazza, BearShare, etc.) and to find other Gnutella clients that are willing to communicate with you. You will communicate directly only with the handful of sites you’ve agreed to contact. Any material of interest to other sites will pass along from one site to another in store-and-forward fashion. Since Gnutella networks use the Internet, if your computer is running Gnutella-based software, you can connect with someone who’s in another country just as easily as within your own region. This means peer-to-peer networks are robust and virtually failsafe.

Under the Gnutella model, the user starts with a networked computer equipped with a desktop version of Gnutella (e.g. LimeWire, Kazaa, BearShare), which is then used in conjunction with an ISP account to connect to the Gnutella network and to announce to all other computers connected to the P2P network that it is alive. The user’s computer can then search the contents of the shared directories of the P2P network, and download the desired files directly from another user’s computer.

The advantage of using this type of P2P network is that it does not rely upon a central server, thus it would be virtually impossible to bring it down. Even if distribution of P2P software were banned, the network itself could still continue with all the current users that have already downloaded the client software onto their computers.

There are different versions of the Gnutella model. Grokster and others have taken the Gnutella model and modified it. For instance, rather than all networked computers passing along each search query, the Grokster distributed self-organizing network recognizes faster computers that utilize a powerful connection (e.g. T-1/E-1) and selects those computers to be what is referred to as “SuperNodes,” which then serve as local search hubs. When a non SuperNode computer connects to the network, its “neighborhood SuperNode” uploads information about that computer’s shared files along with performing searches. The selection of a SuperNode is automatic, there is no manual intervention.

Freenet model. This P2P model is a distributed anonymous information storage and retrieval system. The best way to explain the Free Network Project (i.e. Freenet) is to quote the website’s explanation:

• Freenet is free software that lets you publish and obtain information on the Internet without fear of censorship. To achieve this freedom, the network is entirely decentralized and publishers and consumers of information are anonymous. Without anonymity there can never be true freedom of speech, and without decentralization the network will be vulnerable to attack.
• Communications by Freenet nodes are encrypted and are “routed-through” other nodes to make it extremely difficult to determine who is requesting the information and what its content is.
• Users contribute to the network by giving bandwidth and a portion of their hard drive (called the “data store”) for storing files. Unlike other peer-to-peer file sharing networks, Freenet does not let the user control what is stored in the data store. Instead, files are kept or deleted depending on how popular they are, with the least popular being discarded to make way for newer or more popular content. Files in the data store are encrypted to reduce the likelihood of prosecution by persons wishing to censor Freenet content.
• The network can be used in a number of different ways and isn’t restricted to just sharing files like other peer-to-peer networks. It acts more like an Internet within an Internet. For example Freenet can be used for:
  • Publishing websites or ‘freesites’
  • Communicating via message boards
  • Content distribution

    Freenet is not just theoretical, it has been downloaded by over 1.2 million users since the project started, and it is used for the distribution of censored information all over the world, including countries such as China and the Middle East. Ideas and concepts pioneered in Freenet have inspired hundreds of academic papers in the fields of computer communication, security, and law. Freenet has also received significant coverage in the mainstream press.

NOTE
If you would like a more detailed tutorial on how peer-to-peer networks work visit the howstuffworks website (www.howstuffworks.com/ file-sharing3.htm.) If you would like more information on Gnutella and Freenet’s inner workings there is a very good article by Andy Oram, which can be found at www.oreillynet.com/pub/a/network/2000/05/12/magazine/gnutella.html. Also visit http://freenet.sourceforge.net/ for more information on Freenet.

Yaga model. This is a relatively new P2P technology. Yaga.com has crafted technology that provides built-in security (e.g. files are scanned for viruses before being made available), support for digital rights management, reliable transfer of gigabyte-size files (an increasingly important issue when distributing software and videos), and centralized management (files are given unique signatures based on their size). As soon as a file is made available, it is included in the search index, supporting full-text search (every word, not just the title and description). All the basic elements are there to enable content producers to use the Yaga network as a mechanism for selling content.

For example, with Yaga you can make your files available to a community of users, and also download files made public by others. Budding programmers who have written software that they would like to make available to the world would find Yaga useful. An up and coming rock band that is having trouble getting their music played on the radio can, with the help of Yaga software, make their product readily available to a community of users worldwide.

Yaga may be the best tool if you want to set up your own private branded P2P network. You could then use that network to publish software, a musical library, your latest video concept, photographs, books and manuals, or any other kinds of files — for free or for a price, depending upon your business model.

Content-Addressable Network (CAN) model. We can’t conclude this discussion without addressing the experimental, but very scalable CAN model. Freenet’s aim is to provide anonymity during both file sharing and lookups, and is intended to provide robustness in the face of hostile agents both (legally and technically); whereas, Gnutella was designed to provide a complete solution to file sharing in the post-Napster era. Both P2P systems are designed for immediate deployment. However, CAN is a building block for not only file sharing but also for higher-level services, such as DNS, distributed file systems, etc. While at this writing CAN is still largely a research rather than a production system, keep an eye on its progress. It offers some exciting possibilities. Go to your favorite search engine and perform a search to track the latest developments.

Requirements

To establish a P2P e-commerce operation by becoming a partner or an affiliate of an established P2P network, you need at minimum:

• A niche market group who will open their computers and allow others to upload files directly from their drives.
• A working e-commerce website, of course.
• P2P client software, which you would provide to end-users so they can access the P2P network. Then your targeted market will need to download that software and put their shared files into a folder on their own hard disk.

You can create your own members-only network or become a part of a larger P2P network such as Grokster, Overnet, eDonkey2000 network, kaZaa, or Blubster. It is expected that only a small minority of readers will want to operate their own P2P network — most will want to piggyback onto an already existing network. Thus, the design and maintenance of a P2P network will not be discussed at length in this book. But to point any intrepid soon-to-be P2P operators in the right direction, Peeracy.com (http://peeracy.com) provides source codes (most are free) for various P2P networks. Once you call up the home page, just click on “P2P Software” link. The first downloads listed are for P2P clients. Scroll through those and you will find a number of different source code downloads. And visit the Afternapster.com website. This website not only keeps an up-to-date list of the latest P2P networks and client software, it provides a good, but brief overall review of each product/website.

Read books on P2P networking. For instance, the author learned quite a bit about P2P from reading the Peer to Peer: Harnessing the Power of Disruptive Technologies, Andy Oram (O’Reilly). Other good books include Peer-to-Peer Computing: Technologies for Sharing and Collaborating on the Net, David Barkai (Intel Press), and Peer-to-Peer: Building Secure, Scalable, and Manageable Networks, Dana Moore, John Hebeler (McGraw-Hill Osborne Media).

Business Model

Wondering what P2P has to offer an e-commerce operation? There are ways to make money with P2P, although it is doubtful that you will ever get rich from such an operation. For example, you could —

• Enter into contracts with third party software providers (e.g. Gain, Mysearch, Shopathome, New.net, etc.) who will pay you for distribution of digitally rights-managed files.
• Sell advertising space on the client software that is downloaded onto your customer’s computers.
• Sell a version of the client software that is ad-free.
• Sell products and service that is of interest to your niche market.
• Create content, post that content on your website to encourage people to come to your site, and then sell banner and pop-up advertising space on your website.
• Create a newsletter and sell sponsorships and/or ads.

Table 6: The average download speed for some of the more common files shared over a P2P network.

Media	56 Kbps Modem	Cable (average 512 Kbps)	T-1/E-1 (1.54/ 2 Mbps)
Photo, 200 KB	40 seconds	2 seconds	2 seconds
MP3 Music track	13 min 30 seconds	1 minutes	15 seconds
Full-length movie	22 hours	1 hour 45 minutes	25 minutes
Five-minute video clip	1 hour	6 minutes	2 minutes
Novel, 1 MB	4 minutes	15 seconds	4 seconds

Tips

Your P2P network doesn’t necessarily need to serve music or video enthusiasts. You could use your P2P e-commerce site to enable a community of content developers to share files, or perhaps cooks to share recipes, travelers to share travel journals, cartoonists could share their creations, and programmers also would find P2P a valuable tool. Another idea for using the P2P model is to enable individual stock traders to share court filings, SEC documents, news articles, etc. about various companies — worldwide.

There are many ways a P2P model could be used to enable a niche community to publish their endeavors and easily to share it with a global audience.