P2P Networking and P2P Software

P2P networking has generated tremendous interest worldwide among both Internet surfers and computer networking professionals. P2P software systems like Kazaa and Napster ranked amongst the most popular software applications ever. Numerous businesses and websites have promoted "peer-to-peer" technology as the future of Internet networking.

Although they have actually existed for many years, P2P technologies promise to radically change the future of networking. P2P file sharing software has also created much controversy over the legality and fair use. In general, experts disagree on various details of P2P and precisely how it will evolve in the future.

The P2P acronym technically stands for peer-to-peer. Webopedia defines P2P as:

A type of network in which each workstation has equivalent capabilities and responsibilities. This differs from client/server architectures, in which some computers are dedicated to serving the others.

This definition captures the traditional meaning of peer-to-peer networking. Computers in a peer-to-peer network are typically situated physically near to each other and run similar networking protocols and software. Before home networking became popular, only small businesses and schools built peer-to-peer networks.

Most home computer networks today are peer-to-peer networks. Residential users configure their computers in peer workgroups to allow sharing of files, printers and other resources equally among all of the devices. Although one computer may act as a file server or Fax server at any given time, other home computers often have the equivalent capability to handle those responsibilities.

Both wired and wireless home networks qualify as peer-to-peer environments. Some may argue that the installation of a network router or similar centerpiece device means that the network is no longer peer-to-peer. From the networking point of view, this is inaccurate. A router simply joins the home network to the Internet; it does not by itself change how resources within the network are shared.

When most people hear the term P2P, they think not of traditional peer networks, but rather a peer-to-peer file sharing over the Internet. P2P file sharing systems became the single most popular class of Internet applications in the first decade of this century.

A P2P network implements search and data transfer protocols above the Internet Protocol (IP). To access a P2P network, users simply download and install a suitable P2P client application.

Numerous P2P networks and P2P software applications exist. Some P2P applications work only with one P2P network, while others operate cross-network. Likewise, some P2P networks support only one application, while others support multiple applications.

A good definition of P2P software was proposed by Dave Winer of UserLand Software many years ago when P2P was first becoming mainstream. Dave suggests that P2P software applications include these seven key characteristics:

• The user interface runs outside of a Web browser
• Computers in the system can act as both clients and servers
• The software is easy to use and well-integrated
• The application includes tools to support users wanting to create content or add functionality
• The application makes connections with other users
• The application does something new or exciting
• The software supports "cross-network" protocols like SOAP or XML-RPC

In this modern view of peer-to-peer computing, P2P networks stretch across the entire Internet, not just a home local area network (LAN). Easy-to-use P2P software applications allow both geeks and non-technical people to participate.

The original MP3 file sharing system, Napster became the world's most popular Internet software application almost overnight. Napster typified the new "modern" P2P system defined above: a simple user interface running outside of the browser supporting both file serving and downloads. Furthermore, Napster offered chat rooms to connect its millions of users and performed a new and exciting (in the sense of "controversial") service.

The name Napster referred both to the P2P network and the file sharing client that it supported. Besides being limited, in the beginning, to a single client application, Napster employed a proprietary network protocol, but these technical details did not materially affect its popularity.

When the original unregulated Napster service was shut down, a number of P2P systems competed for that audience. Most Napster users migrated to the Kazaa and Kazaa Lite software applications and the FastTrack network. FastTrack grew to become even larger than the original Napster network.

Kazaa has suffered from its own legal troubles, but various other systems, like eDonkey / Overnet, have continued the legacy of free P2P file-sharing software.

No one P2P application or network enjoys exclusive popularity on the Internet today. Popular P2P networks include:

• eDonkey
• BitTorrent
• Gnutella

and popular P2P applications include

• eMule
• BitTorrent
• Limewire

Many businesses have been inspired by the success of P2P applications and are busily brainstorming potentially interesting new P2P software. However, some in the networking community believe that the success of Napster, Kazaa, and other P2P applications have little to do with technology and more to do with piracy. It remains to be proven whether mass-market P2P systems can translate into profitable business ventures.

The "P2P" acronym has become a household term. The term refers to a combination of things: software applications, network technologies, and the ethics of file sharing.

In the years ahead, expect the concept of P2P to continue evolving. The networking industry will introduce a wider range of peer-to-peer applications that should compete for attention with traditional desktop and client/server systems. P2P protocol standards will be adopted to a greater extent. Finally, the ramifications of free P2P application information sharing on copyright and intellectual property law will slowly be settled through the process of public debate.