Internet and the World Wide Web - Lecture 11

Internet and the World Wide WebLecture 11Summary of PreviousIntroduction to TelecommunicationsBasic Components of Communications Telecommunications Media Rate of data transferEssential computer Network TerminologiesNetwork TopologyClassification of Computer NetworksNetwork DevicesRecognize the individual components of the big picture of computer networksSummary of PreviousComputer Network LayoutsMicrocomputer-to-local area networkMicrocomputer-to-InternetLocal area network-to-local area networkPersonal area network-to-workstationLocal area network-to-metropolitan area networkLocal area network-to-wide area networkSummary of PreviousSensor-to-local area networkSatellite and microwaveCell phonesComputer terminal / microcomputer-to-mainframeToday’s Lecture The InternetHistoryResource that can be sharedApplications of InternetClient/Server ArchitectureInternet Service ProvidersHTMLWeb BrowsersToday’s LectureSearching the WebTips and TechniquesSearch ProcessDifferent Web search toolsOutlook ExpressSummaryThe InternetWhat is the Internet?A global network of networksIt is based on Internet Protocol (IP)A standard (Language) used over internet for computers to communicate with each other.Who can Join Internet?Anyone with a computer and internet connection.At home, office, public places etc.Any network can join the InternetIncludes research, academic, community & commercial networksPakistan have seen tremendous growth of internet in past few years.Internet at different placesPopularity of InternetImpact of Internet on SocietyThe InternetConnects over a hundred thousand networks from nearly 200 countries.According to Internet World Statistics, internet users are 32.7% of total world population, with the annual growth of 528.1%. (2011 Report)Internet Growth Rate in PakistanUp till 2010 16.78% of Pakistan Population was using Internet Where did internet come from?Late 1960s, ARPA (Advanced Research Projects Agency). Supported by Department of Defense, USA. To share information within one university.ARPANET. To connect USA universities and organizations to share info and communicate. TCP Protocol.1973 – ARPANET connects to EuropeThe ARPANET TeamBrief HistoryMid-1980s – NSFNet (National Science Foundation Network, USA)Formed network between supercomputersInternet of NSFNet was the link to ARPANETNo commercial traffic allowed1990sARPANET shut downNSFNet abandonedCommercial networks take overWhat’s so special about the Internet?Developed for information and project sharing (academic purposes).Original intentionto allow different machines to understand each other.Excellent for broadcasting data and connecting computers: less reliable for security.What can be shared over internet?Many subjects and formats available to shareDocumentsGraphics, video & audioSoftware (free & shareware)NewspapersDirectoriesLibrary catalogues & databasesBooks & journalsJunkHEC Pakistan Online Digital LibraryPakistani Internet Daily NewspaperInternet ApplicationsElectronic Mail (email)A method of exchanging digital messages from an author to one or more recipients.Some early email systems required that the author and the recipient both be online at the same time, in common with instant messaging. Modern email operates across the Internet or other computer networks. Domain mail server collects incoming mail and transmits outing mail EmailInternet ApplicationsFile Transfer Protocol (FTP) It is a standard protocol used to exchange and manipulate files over internetIts purpose is to remotely share files and softwareInternet ApplicationsVoice Over IP (VoIP) VoIP (voice over IP) is an IP telephony term for a set of facilities used to manage the delivery of voice information over the Internet.Internet ApplicationsTelnet A program that runs over your PC and connects it to a server on the network. You can enter commands using Telnet program and they will be executed as if you were directly entering them on the server command prompt. This allows you to control the server and communicate with other servers on the network.Telnet ExampleInternet ApplicationsWorld Wide Web Web, is a way of accessing information over the medium of the Internet. It is an information-sharing model that is built on top of the Internet.It uses HTTP (Hyper Text Transfer Protocol) for communicationWeb uses Web Browsers such as Internet Explorer. Firefox etc. to send data from one end to another end World Wide WebWeb page is a document that needs to be fetchedBrowser gets documents from Web serverWeb Server is the place where web pages are stored/hostedDocuments identified by Uniform Resource Locator (URL) e.g; Web PagehttphyperlinksVertical Scroll barEnter URL in Address barThe World Wide Web - created to link documents held on different machines.Developed at CERN by Tim Berners-Lee.Employed existing ideas but employed in a new way on a vast scale.Graphical browsers developed slightly later.Client/Server ArchitectureWWW is based on a client/server architecture – processing at both endsHere it isA computer elsewhereon the Internet holdinginformationDesktop ClientRemote ServerRequest made using httpYour desktop computerGive me file XWho is ISP?Internet Service Provider (ISP)Company that provides Internet accessDialupConnects to Internet through phone lineModem connects to the phone lineSlow connectionAccess the Internet through ISPHigh-speed accessConnect through a special line2 – 25 times faster than dialupDSL, Cable, T1 are commonHyper Text Markup LanguageHTML is used to make web pages.IT describes how the web page may look like.Simple Code syntax.....Web BrowsersUsed to read and translate HTML Display web contentsDifferent browsers exists.Microsoft Internet ExplorerMozilla FireFoxOperaChrome SafariSearching the WebSearch EnginesSearch engines are:Web sites used to find information on the InternetSearches are based on:A word or a combination of words or topicsExamples of search engines are MSN, Google and AltaVista.Search ExampleTo find some food recipes on the internet MSN home page appears as shownOpen the MSN home pageType in some text and click the link Search buttonSearch ExampleHow to perform searchUse specific questionsA specific question is a question that you can phrase easily and one for which you will recognize the answer when you find itAvoid explanatory questionsAn explanatory question is an open-ended question that can be harder to phrase; it also is difficult to determine when you find a good answerExamples of QuestionsSpecificWhat is the population of Pakistan.Statistics will be shown as a result.Explanatory What causes depression?Because there are multiple reasons which causes depression.Not a single answer Web Search Process Before beginning a Web search, decide whether the question is specific or exploratory.Search ProcessUsing Search EnginesWeb search tools include four broad categories of sites:Search enginesDirectoriesMetasearch enginesOther Web resources such as Web bibliographiesNew Perspectives on the Internet, 8th EditionUsing Search EnginesA Web search engine is a Web site (or part of a Web site) that finds other Web pages that match a word or phrase you enterThe word or phrase you enter in a search engine is called a search expressionA hit is a Web page that is indexed in the search engine’s database and that contains text that matches a specific search expressionNew Perspectives on the Internet, 8th EditionGoogle Search EngineNew Perspectives on the Internet, 8th EditionUsing Search EnginesUsing Web Directories It specializes in linking to other web sites and categorizing those links.It lists web sites by category and subcategory. Not a search engine by itself.Web Directory ExampleNew Perspectives on the Internet, 8th EditionUsing Search EnginesUsing Metasearch Engines:A metasearch engine is a tool that combines the power of multiple search enginesNew Perspectives on the Internet, 8th EditionUsing Search EnginesUsing Web Bibliographies:The Web includes Web bibliographies, another category of resource for searching the Internet.Web bibliographies are also called resource lists, subject guides, clearinghouses, and virtual librariesConfiguring Email Client on ComputerConfiguring Outlook ExpressAn e-mail client:Is a computer program that is used to send and receive e-mail Advantages of an e-mail client:To compose e-mails offlineTo manage e-mails on your own PCConfiguring Outlook ExpressMicrosoft Outlook Express :Is one of the popular email client applicationsLets you compose as many messages without having to connect to the InternetConfiguring Outlook Express for Hotmail (Contd..)123Configuring Outlook ExpressThe Internet Connection Wizard is displayed Click NextEnter your name in the Display name boxConfiguring Outlook ExpressType the e-mail address in the E-mail address box Click NextConfiguring Outlook ExpressClick HTTP in the Server boxClick Hotmail in the My HTTP mail service provider box Click NextConfiguring Outlook Express for Hotmail (Contd..)Type your Hotmail address in the Account name box Type your password in the Password box Click NextConfiguring Outlook ExpressA congratulations message is displayedClick FinishConfiguring Outlook ExpressClick YesThe Outlook Express dialog box appears Configuring Outlook ExpressOutlook Express will download the files from your Hotmail inbox and display them SummaryWe have learnt today,Internet is anElastic and robust networkNo single centreBrief History of Internetwww is not the only resource on the InternetOther resources includesEMAILFile Transfer ProtocolTelNetVOIPSummaryClient/Server ArchitectureISPHTMLWeb BrowsersSearching The WebSearch EnginesHow to Perform SearchWeb Search ProcessConfiguring Outlook ExpressWWW - World Wide Web Distributed multimedia hypertext systemHTML - Hyper Text Mark up LanguageNative language for documents on the WWWHTTP - Hyper Text Transfer ProtocolSet of rules for communication between client & serverURL - Uniform Resource LocatorAddress of an object on the InternetSummary of Important Terminologies