The Internet and the World Wide Web

Una DooneyThe Internet and WWWSlide 2 What is the Internet? A collection of networks (LANS and WANS) around the world that can to communicate with each other The physical infrastructure or backbone is made up of: –Computers –Cables –Satellites

Una DooneyThe Internet and WWWSlide 3 The Global Network Satellites Computers Cables Servers Users ISPs

Una DooneyThe Internet and WWWSlide 4 WWW Structure

Una DooneyThe Internet and WWWSlide 5 What is The Word Wide Web (WWW)? The URL or web address uses a set of protocols that allows different types of computers and operating systems to ‘talk’ to each other The URL is a ‘translating’ device

Una DooneyThe Internet and WWWSlide 6 Hypertext Hypertext is the code used to prepare pages for viewing (HTML tags etc) Hypertext links are placed throughout web pages that allow the user to jump from place to place (site to site)

Una DooneyThe Internet and WWWSlide 7 Browser The Browser is the software used to explore the internet –Internet Explorer (Microsoft) –Netscape Navigator (Mark Andreesen)

Una DooneyThe Internet and WWWSlide 8 Protocols Are the rules followed to communicate over the WWW –http – hypertext transfer protocol –URL – Uniform Resource Locator –FTP – File transfer protocol –TCP/IP – Transmission Control Protocol/ Internet Protocol

Una DooneyThe Internet and WWWSlide 9 URL – Uniform Resource Locator A URL or Web Address is made up of a number of parts It represents the unique address of an internet site or file

Una DooneyThe Internet and WWWSlide 10 ISP – Internet Service Provider A company that provides access A monthly fee (or sometimes free) gives you –The necessary software package –A username and password –An access phone number Equipped with a modem, you can then log on to the internet and browse the WWW and send and receive slog on

Una DooneyThe Internet and WWWSlide 11 Web Server This is a very large computer which holds website files

Una DooneyThe Internet and WWWSlide 12 HTTP HTTP (Hypertext Transfer Protocol) –It transports ‘hypertext’ documents over the internet –The user enters an address (URL) in the browser, which identifies a file on a web server –The file is located, sent to the users computer and interpreted by the browser, after which it can be displayed on the screen

Una DooneyThe Internet and WWWSlide 13 HTTP With HTTP the file itself is not sent to us – only a copy that is held in the browser’s ‘cache’ or temporary memory

Una DooneyThe Internet and WWWSlide 14 IP Address Every computer connected to the internet needs an IP address –Example ( ) For intuitive reasons these are often replaced by Domain Names such as intel.com or microsoft.com pressroom/links.htm

Una DooneyThe Internet and WWWSlide 15 The URL In order to find a particular file the system needs to know the path, folder, and file name of what is being requested (its exact location on the server) pressroom/links.htm

Una DooneyThe Internet and WWWSlide 16 FTP We use FTP (File Transfer Protocol) to ‘download’ files from a web server to our own computer If we want a permanent copy of a file from the internet stored on our computer we must use FTP FTP is also used to ‘upload’ files to a web server

Una DooneyThe Internet and WWWSlide 17 Downloading Files We need to consider copyright issues before downloading and using files from the internet Viruses can infect your computer from downloaded files or s Lots of files - programs, text, graphics, images, even sounds - are available to be copied without restriction

Una DooneyThe Internet and WWWSlide 18 TCP/IP Transmission Control Protocol / Internet Protocol Controls all traffic on the internet A standard method for transferring data

Una DooneyThe Internet and WWWSlide 19 TCP/IP ISPs have fixed IP addresses but ordinary users will have dynamic IP addresses A large file is broken up to be transported across the internet

Una DooneyThe Internet and WWWSlide 20 TCP/IP - a two-layer program TCP Breaks messages into smaller ‘packets’ for transmission Ensures that all the bits are put together at the other end

Una DooneyThe Internet and WWWSlide 21 IP Handles the address part of each ‘packet’ so that it gets to the right destination

Una DooneyThe Internet and WWWSlide 22 People Tim Berners-Lee –developed the system of hyper- linking Mark Andreesen – developed the first web browser

Una DooneyThe Internet and WWWSlide 23 Factors leading to Growth of the WWW –Fall in cost of computers –Smaller computers –Development of protocols and standards –Hypertext – clickable links –New web browser software –Growth in networking – LANs and WANs

Una DooneyThe Internet and WWWSlide 24 Uses of Internet E-commerce/Shopping Making Bookings (travel) Research/Education News Chat/Entertainment

Una DooneyThe Internet and WWWSlide 25 Today About 4.3 billion IP addresses at present Millions spent every day online Millions do business and communicate every day over the ‘net’

Una DooneyThe Internet and WWWSlide 26 Reading From S: drive Domain Names Brief History of the WWW Lecture Notes Computers – Tools for an Information Age by H L Capron and J A Johnson Ch 8