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The Internet Concepts covered •What is the Internet •History of the Internet •How does the Internet work •Getting connected •Internet applications James Tam A Network: A Bunch of Connected Computers Hub or switch Router Hub or switch James Tam The Internet: A Gigantic Network of Networks James Tam Arpanet: The Parent of the Internet Research network (U.S. Department of Defense) Huge network • Eventually spanned much of the U.S. Designed to remain functional in the case of disaster or war • Existing system (single path connection) James Tam Arpanet (Continued) Designed to remain functional in the case of disaster or war • New system (multiple paths – allows for alternatives) Designed to transport many kinds of data Initiated and completed during the cold war • Started in 1957 in response to the Soviet space program • First went on the air in the summer of 1969 James Tam Growth Of The Arpanet Over Time a) December 1969 b) July 1970 c) March 1971 d) April 1972 September 1972 From Computer Networks by Tanenbaum James Tam Birth And Growth Of The Internet 1983 MILNET • The military portion of the Arpanet separates into it's own network Mid 1980's • People began to view the Arpanet network as 'the Internet'. 1986 NSFNET • Designed by the U.S. National Science Foundation (NSF) as a high speed successor to the Arpanet • Created as it's own network connected to the Arpanet and increased it's overall speed. NSFNET (fiber optic) Arpanet (phone lines) James Tam Birth And Growth Of The Internet (Continued) 1990 The original Arpanet abandoned in favour of the higher speed connections of the NSFNET NSFNET (fiber optic) Arpanet (phone lines) • 3,000 networks and 200,000 computers The size of the Internet approximately doubles each year (Paxson 1994) James Tam Protocols: The Rules That Make It All Possible Protocols in real life • Rules for determining the format of communication Ciao? Hello! Hello? Bonjour? Hello! Hello! Hola? James Tam Computer Protocols Determines the format and method of communication Internet protocols • TCP/IP (Transmission Control Protocol/ Internet Protocol) TCP/IP •Amiga •Canada •Send email The Internet TCP/IP •Windows •U.S.A •Get video TCP/IP •PowerPC •U.K. •Send picture James Tam Connecting Your Computer To The Internet Requires you to sign up with an Internet Service Provider (ISP) The Internet Your computer ISP Types of Internet connections • Old phone dialup connections • Faster phone line connections • Cable connection James Tam Old Phone Dialup Connections Having your computer call another computer to connect to the Internet Problem: Phone lines and computers don't easily mix From the The Complete Idiot's Guide to High Speed Internet Connections by Soper James Tam Old Dialup Connections (Continued) Requires a modem (modulator/demodulator) From the The Complete Idiot's Guide to High Speed Internet Connections by Soper Very slow (300 – 56,000 bps/56Kbps) Cheap ($20.00/month) Uses up a phone line May not allow for a continuous internet connection James Tam Faster Phone Line Connections Types of fast phone line connections • ISDN (Integrated Services Digital Network) • DSL (Digital Subscriber Line) - ADSL (Asymmetrical DSL) James Tam ISDN (Integrated Services Digital Network) Allows internet connections at about twice the max speed of a regular modem connection (128 Kbps) Allows for a dialup internet connection An older technology being replaced by DSL James Tam DSL/ADSL Uses a single wire for voice and data (computer) From the The Complete Idiot's Guide to High Speed Internet Connections by Soper Uses a different sound frequency for each James Tam DSL/ADSL (Continued) Faster than regular dialup • ~ 100's Kbps – several Mbps Allows for a continuous internet connection James Tam DSL/ADSL ADSL (Asymmetrical DSL) • You can download information (get information from the internet) faster than you can upload it (send information somewhere to the internet) • Costs about $35.00/month Upload 32 – 300 Kbps The Internet Your computer Download 1.5 – 8 Mbps James Tam Cable Connections To The Internet Uses a coaxial (cable TV) connection From the The Complete Idiot's Guide to High Speed Internet Connections by Soper Employs unused T.V. channels James Tam Cable Connections To The Internet (Continued) Fast connection • "100 times faster than dialup" • approximately several Megabits (1 – 3 Mbps) per second download • Approximately several hundred thousand Kilobits (200 – 300 Kbps) upload A bit more ($40.00/month plus installation) Allows for a continuous internet connection James Tam Cable Connections To The Internet (Continued) Problem: You are not alone in your cyberspace connection Dialup 56 Kbps DSL/ADSL ~128 Kbps – 3 Mbps Cable Modems several Mbps (shared) The Internet James Tam Speed Of Your Internet Connection The Internet It is limited by the speed of the slowest path James Tam Characteristics Of The Internet Dynamic routing Delivery of information through packets James Tam The Internet: Dynamic Routing The Internet As long as the source and destination are connected to the Internet the information will be transmitted James Tam Tracing The Route Of Your Packets: tracert / traceroute U of C Telus Sprint James Tam The Internet: Packets (Real-life analogy) From the The Complete Idiot's Guide to High Speed Internet Connections by Soper James Tam The Internet: Packets Information sent on the Internet is broken down into packets The packets may or may not be sent along the same route from the source to the destination Source ? ? ? The Internet James Tam The Internet: Packets (Continued) At the destination the packets are checked and reassembled The Internet Destination James Tam The Internet Society An international professional organization headed by a Board of Governors A portion of the Internet Society's mission • To promote the use of the Internet • To facilitate the development of standards, protocols and administration of the Internet •… Not a managing organization! For further details http://www.isoc.org James Tam The Internet: Applications Original set of applications of the Internet • Email • News • Remote login (telnet, rlogin and ssh, Stel) – lets you login to a computer from outside the network • File transfer (ftp, ssh) – download / upload information World Wide Web (WWW) • Consisted of documents containing text, pictures, sound, video and links to other documents. James Tam HTML (Hypertext Mark-up Language) Used to create typical web pages Hypertext • Points to another document (indicated through the URL) • Documents end with the suffix ".html" Mark-up • Style instructions (e.g., bolding or italicizing text, bulleting lists, inserting images etc) Language • HTML is not a programming language! • It's a language that allows you to create documents that will be a part of the WWW James Tam URL's (Uniform Resource Locator) Provide a standardize way of describing information Parts of a url (each part is enclosed by angled brackets) <protocol> <machine where document is located> <path to the document> e.g., http://www.gamespot.com http – indicates a hypertext document (a web page) www.gamespot.ca - a place on the world wide web (web sever) James Tam URL's (Continued) e.g., http://www.ucalgary.ca/~jrtam/personal_pics/hohoho.jpg http://www.ucalgary.ca/ ~jrtam /personal_pics/ hohoho.jpg Account: jrtam THE INTERNET public_html ACS Web Server index.html personal_pics hohoho.jpg James Tam Types Of Domain Names Suffixes at the end of the url Generic com edu gov mil Countries org net ca jp com…commercial edu…educational institutes gov..the U.S. federal government mil…U.S. armed forces org…non-profit organizations net…Network providers James Tam Email Addresses similar to web addresses Three main parts: Format: <person's name> @ <host>.<domain> Example: [email protected] .ca…top level domain (Canada) ucalgary…domain name for the University of Calgary cpsc…the name of the Computer Science network at the U of C tamj..my login name for cpsc network James Tam The World Wide Web: Web Servers Computer running web browser – person clicks on link 1) Browser determines URL 2) Browser connects to the server with that URL Sever containing a web page 3) The server sends back information about the link (web page) 4) The browser displays the web page James Tam Plug-ins For Web Browsers Extend the basic features of web browsers Can be downloaded from the web Examples: • • • • QuickTime (Apple) RealPlayer (Real) ShockWave Flash (Macromedia) Acrobat (Adobe) James Tam Internet2 A non-profit consortium of 190 universities partnered with industry and government Goal is not to replace the Internet but to improve it For more information see: http://www.internet2.edu James Tam Intranets A mini version of the Internet Provides the features of the Internet (e.g., web pages) but is self enclosed • Cannot be accessed from the outside • Uses the protocols of the Internet James Tam Summary How the Internet can be viewed as a vast network of networks The origins of the Internet and how did it evolve into its present (and still evolving state) How is the Internet interconnected and how is information transmitted across it (packets, dynamic routing) What are the different ways of establishing a connection to the Internet • Dialup, DSL/ADSL, Cable What are the main applications of the Internet Email, File Transfer, Remote Login, News, The World Wide Web James Tam