Contrary to some common usage, the Internet and the World Wide Web are not synonymous: the Internet is a collection of interconnected computer networks, linked by copper wires, fiber-optic cables, wireless connections etc.; the Web is a collection of interconnected documents, linked by hyperlinks and URLs, and is accessible using the Internet.
Creation of the Internet
The USSR’s launch of Sputnik spurred the U.S. to create the Defence Advanced Research Projects Agency (DARPA) in February 1958 to regain a technological lead. DARPA created the Information Processing Technology Office to further the research of the Semi Automatic Ground Environment program, which had networked country-wide radar systems together for the first time. J. C. R. Licklider was selected to head the IPTO, and saw universal networking as a potential unifying human revolution. Licklider recruited Lawrence Roberts to head a project to implement a network, and Roberts based the technology on the work of Paul Baran who had written an exhaustive study for the U.S. Air Force that recommended packet switching to make a network highly robust and survivable. After much work, the first node went live at UCLA on October 29, 1969 on what would be called the ARPANET, the “eve” network of today’s Internet. In December of 1970, Charles A. Petrik contacted the U.S. Navy and suggested that a special communications network, that the Department of Defence had built for use in the possibility of a nuclear attack, could also be used during peace time. Petrik convinced the military to connect the computers of the U.S. National Laboratories for scientific research purposes, and to allow these labs to get data to other labs faster, and safer. The vast majority of today’s Internet uses version four of the IP protocol (i.e. IPv4), and although IPv6 is standardised, it exists only as “islands” of connectivity, and there are many ISPs who don’t have any IPv6 connectivity at all. The first TCP/IP wide area network was operational by 1 January 1983 , when the United States’ National Science Foundation (NSF) constructed a university network backbone that would later become the NSFNet. (This date is held by some to be technically that of the birth of the Internet.) It was then followed by the opening of the network to commercial interests in 1995. Important separate networks that offered gateways into, then later merged into the Internet include Usenet, Bitnet and the various commercial and educational X.25 networks such as Compuserve and JANET. The ability of TCP/IP to work over these pre-existing communication networks allowed for a great ease of growth. Use of Internet as a phrase to describe a single global TCP/IP network originated around this time.
The network gained a public face in the 1990s. In August 1991 CERN in Switzerland publicized the new World Wide Web project, two years after Tim Berners-Lee had begun creating HTML, HTTP and the first few web pages at CERN in Switzerland. In 1993 the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign released the Mosaic web browser version 1.0, and by late 1994 there was growing public interest in the previously academic/technical Internet. By 1996 the word “Internet” was common public currency, but it referred almost entirely to the World Wide Web.
Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks such as FidoNet have remained separate). This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network.
Today’s Internet
Apart from the complex physical connections that make up its infrastructure, the Internet is held together by bi- or multi-lateral commercial contracts (for example peering agreements) and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is essentially defined by its interconnections and routing policies.
Internet protocols
In this context, there are three layers of protocols:
| • | at the lowest level is IP - the datagram which carries a block of data from one node to another |
| • | next comes TCP & UDP - the protocols by which one host exchanges data with another – the former making a virtual circuit giving some level of guarantee of reliability, the latter being a best-effort connection-less transport |
| • | on top comes the application protocol - the specific messages or data stream used by the |
| • | application running on the hosts to talk to each other. |
Unlike older communications systems, the Internet protocol suite was deliberately designed to be independent of the underlying physical medium. Any communications network, wired or wireless, that can carry two-way digital data can carry Internet traffic. Thus, Internet packets flow through wired networks like copper wire, coaxial cable, and fibre optic; and through wireless networks like Wi-Fi.
Together, all these networks, sharing the same high-level protocols, form the Internet.
The Internet protocols originate from discussions within the Internet Engineering Task Force (IETF) and its working groups, which are open to public participation and review. These committees produce documents that are known as Request for Comments documents (RFCs). Some RFCs are raised to the status of Internet Standard by the IETF process.
Some of the popular services on the Internet that make use of these protocols are e-mail, Usenet newsgroups, file sharing, Instant Messenger, the World Wide Web, Gopher, session access, WAIS, finger, IRC, MUDs, and MUSHs. Of these, e-mail and the World Wide Web are clearly the most used, and many other services are built upon them, such as mailing lists and blogs. The Internet makes it possible to provide real-time services such as Internet radio and webcasts that can be accessed from anywhere in the world.
World Wide Web
The World Wide Web (“WWW” or simply the “‘Web”) is a global information space which people can read-from and write-to via a large number of different Internet-connected devices. For example, computers, Personal Digital Assistants, cellular phones, telephone kiosks, etc. The World Wide Web is also available (sometimes only partially) through digital television services, exposing content onto television screens.
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