So how does the Internet work? It is important to remember the Internet is a network of computer networks interconnected by communications lines of various compositions and speeds. Interspersed across this immense network are routers which either guide traffic to specific destinations or keep it within well defined areas. This vastness of scale can be distilled into two basic actions: requests for information and the servicing of such requests, which forms the relationship between the two types of computer using the Internet: clients and servers. Whether connected to a local area network (LAN) at a place of business or attached by cable modem from home, computers requesting information across a network or the Web are generally regarded as clients; machines supplying the information are servers. In practice the distinction is less polarised, with many computers both requesting and delivering information, but the premise forms the basis of the Internet.
Servers often perform specific duties: web servers hosting websites, email servers forwarding and collecting email, FTP (File Transfer Protocol) servers uploading and downloading files.
Access to the Web for home users is achieved by dial-up modem, cable (broadband or ADSL), Fibre-Optic, or wireless connection to their ISP (Internet Service Provider); business users will typically be connected to a local area network and gain access via a communications server or gateway, which is again linked through an ISP to the Web. ISPs themselves may be connected to larger ISPs, leasing high speed fibre-optic communications lines. Each of these forms a gateway to the Web with the largest maintaining the 'backbones' of the Web through which run the international 'pipes' connecting the world's networks.
TCP/IP (Transmission Control Protocol/Internet Protocol) is the governing set of protocols used for transmitting information over the Internet. It establishes and manages the connection between two computers and the packets of data sent between them.
Each computer connected to the Internet has a unique IP address assigned to it, either dynamically at the moment of connection or for a period of a day or so, or (for all intents and purposes) a fixed or static address like that assigned to a web or name server hosting websites. The current version of IP, version 4, allows for 4.3 billion unique addresses – thought more than adequate a few years ago but, as there are now only a billion left, no longer sufficient to address not only the volume of new users and hosts coming online but also the influx of new technologies demanding attendant IP addresses such as those associated with smart internet-enabled machines like auto-ordering fridges, Pepsi dispensers and media centres and now internet phones. However, the shortfall is being remedied with the emergence of IPv6 and its 340 billion billion billion address slots which not guarantees practically limitless web access but also offers intrinsic unbreakable security encryption levels.
ICANN, the Internet Corporation for Assigned Name and Numbers is the non-profit North American organisation responsible for Internet IP address space allocation and DNS management, among other technical management functions.
Most users have no need to know the unique identities of computers with which they communicate since software deals with this on their PC, they simply address their email to whomever or logon to their shared network drive and drill down folders to load a file to work on.
An IP address looks like 18.104.22.168, a cluster of four numbers known as octets. People don't think of addresses in such a way – although they have been forced to for some time with phone and cell numbers and their PINs for credit cards – but, as with email, use names as mnemonics. As the Internet grew, it became obvious users seeking specific machines would need some method of identifying and recalling computers quite apart from IP addresses.
"The Internet in Practice Part 4" The Internet Explained. 23 Novermber 2005. Written by Vincent Zegna and Mike Pepper