The Internet and the World Wide Web (WWW) are not synonymous. The Internet is the physical computer system that consists of an international internetwork of networks that link millions of computers and allow information to be transferred between any node within the system. The World Wide Web is the accessible information available over the Internet which is in the form of documents, multimedia or any other standard file format available for transfer over the Internet.
The Internet – Origins
The Internet began life as ARPANET, a large Wide Area Network (WAN) which was developed by the American Department of Defence during the cold war. ARPANET was a distributed system that was not built around a central communications center that could be destroyed by a nuclear attack. If one node failed, information could be transferred or reroutedaround the broken node to provide reliable communication.
The Internet is simply the interconnection of computer networks with a router at each node to select the next node in the path towards the destination. Routing of information is achieved using as a non-proprietary protocol developed by the American Department of Defence called TCP/IP. This protocol is a set of rules that define the manner in which information is divided into smaller packets, routed through the system to a specific destination and reassembled into its original form.
After the war the US academic science network used by research institutions and universities was given access to ARPANET. Later the businesses community and then the general public where given access. This quickly grew into a large inter-networked system well before the World Wide Web was developed.
Structure of Internet
Although the Internet appears to the user as a internetwork of networks, it is actually structured in a hieratical fashion similar to a tree structure, with a higher speed national and international backbone connection at the top. At the bottom of the tree, individuals and businesses connect to an Internet Service Provider (ISP). Above the ISP’s are the Internet Access Providers (ASP’s) and above them the National Access Provider (NAP) who provides the national high speed backbone to handle the vast quantity of national Internet traffic, and also connect internationally to NAP’s in other country domains.
User connections to an ISP may be via dial-up modem and normal phone line, or a permanent high speed digital line for a larger business.
The World Wide Web
The world wide web consists of the collection of hypertext documents and associated files which are formatted according to Hypertext standards and are accessible via the Internet. It was developed by the scientists at the European high energy physics center (CERN) in response to the different services and different text mode interfaces used on the Internet. They created a single protocol for linking, retrieving and viewing documents which used a single application termed a browser to display documents on screen with hyperlinks for navigation.
The National Centre for Supercomputing Applications (NCSA) then developed a browser called Mosaic in 1993 that included a graphic user interface. Its author Marc Andreessen later left the NCSA and founded the Netscape Communications Corporation.