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									Eastern Mediterranean University
School of Computing and Technology
Department of Information Technology


                   ITEC229
 Client-Side Internet and Web Programming



  Introduction to Internet
  and World Wide Web
   CHAPTER 1




 Prepared by: R. Kansoy


                                       LOGO
                            Contents


    1.1 What is Internet?
    1.2 History and Development of the Internet
    1.3 Internet Standards & Coordination
    1.4 Anatomy of the Internet
    1.5 Bacis Internet Protocols
    1.6 Technologies/Tools of the Internet
    1.7 World Wide Web




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                1.1 What is Internet?


 The Internet, sometimes called simply "the Net," is a
  worldwide system of computer networks - a network of
  networks in which users at any one computer can, if they
  have permission, get information from any other computer
  (and sometimes talk directly to users at other computers).

 Originally the Internet served to interconnect laboratories
  engaged in government research, and since 1994 it has
  been expanded to serve millions of users and a multitude
  of purposes in all parts of the world.

 In a matter of very few years, the Internet has
  consolidated itself as a very powerful platform that has
  changed the way we do business, and the way we
  communicate.



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                 1.1 What is Internet?


 The Internet, as no other communication medium, has
  given an International or, if you prefer, a "Globalized"
  dimension to the world.

 Internet has become the Universal source of information
  for millions of people, at home, at school, and at work.

 Internet is actually the most democratic of all the mass
  media. With a very low investment, anyone can have a web
  page in Internet.

 This way, almost any business can reach a very large
  market, directly, fast and economically, no matter the size
  or location of the business.

 With a very low investment, almost anybody that can read
  and write can have access to the World Wide Web.

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        1.2 History and Development of the Internet



 It was conceived by the Advanced Research Projects Agency
  (ARPA) of the U.S. government in 1969 and was first known as
  the ARPANet.

 The original aim was to create a network that would allow users of
  a research computer at one university to be able to "talk to"
  research computers at other universities.

 In time, ARPANET computers were installed at every university
  in the United States that had defense related funding.

 Gradually, the Internet had gone from a military pipeline to a
  communications tool for scientists.

 As more scholars came online, the administration of the system
  transferred from ARPA to the National Science Foundation.


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       1.2 History and Development of the Internet

         Brief History of the Internet

 1960 - US government seeks nuclear war proof
         communications, briefs project to APRA

 1968 - DARPA (Defense Advanced Research Projects
         Agency) contracts with BBN (Bolt, Beranek &
         Newman) to create ARPAnet

 1969 - Birth of Internet. Universities and researches
         connected to ARPAnet.

 1970 - First five nodes:
             UCLA
             Stanford
             UC Santa Barbara
             University of Utah, and
             BBN

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        1.2 History and Development of the Internet



 ARPANET

     Implemented in late 1960’s by ARPA (Advanced Research
      Projects Agency of DOD)

     Networked computer systems of a dozen universities and
      institutions with 56KB communications lines

     Grandparent of today’s Internet

     Intended to allow computers to be shared

     Became clear that key benefit was allowing fast communication
      between researchers – electronic-mail (email)


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        1.2 History and Development of the Internet

          Brief History of the Internet
 1971 - Ray Tomlinson creates first network email application.
            E-mail - a program to send messages across a
             distributed network.
 1972 – Telnet - Computers can connect more freely and easily
 1973 – FTP - computers send and receive data.
 1974 - TCP specification by Vint Cerf
 1977 - ARPAnet engineers realise the network is going to grow
         beyond expectations
 1983 - ARPAnet switched NCP to TCP/IP
 1984 - Domain Name System (DNS) was introduced.
 1989 - Tim Berners-Lee proposes a new set of Internet protocols
 1991 - World-Wide Web - developed released by CERN; within the
         UK academic network.
 1992/93 - Mosaic/Netscape - User Friendly Graphical Front
 1995 - US government releases Internet for commercial use


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         1.3 Internet Standards & Coordination



     ICANN - The Internet Corporation for Assigned
              Numbers & Names
       Non-profit organization
       Main function is to coordinate the assignment of:
         • Internet domain names
         • IP address numbers
         • Protocol parameters
         • Protocol port numbers.




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          1.3 Internet Standards & Coordination


      Internet Engineering Task Force (IETF)

        http://www.ietf.org/
        Founded 1986
        Request For Comments (RFC) at
         http://www.ietf.org/rfc.html




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         1.3 Internet Standards & Coordination



      W3C – World Wide Web Consortium

        Develops recommendations and prototype
         technologies related to the Web

        Produces specifications, called
         Recommendations, in an effort to
         standardize web technologies




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                1.4 Anatomy of the Internet

      Internet Backbone
       A high capacity communication link that carries data
       gathered from smaller links that interconnect with it.


                                          NAP – Network
                                           Access Point
                                            Access points or
                                            junctions to the
                                            Internet Backbone
                                            in major cities.




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                1.4 Anatomy of the Internet


 Client/Server can describe a relationship between two
  computer programs – the "client" and the "server".

 Client
    requests some type of service (such as a file or database
     access) from the server.

 Server
    fulfills the request and transmits the results to the client
     over a network
 The Internet Client/Server Model
    Client -- Web Browser
    Server -- Web Server



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               1.4 Anatomy of the Internet


 Web Client
   Connected to the Internet when needed
   Usually runs web browser (client) software such as
    Internet Explorer or Netscape
   Uses HTTP (Hypertext Transfer Protocol)
   Connect to a web server using URL information
   Requests web pages from server
   Receives web pages and files from server
   Display the formatted information




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                1.4 Anatomy of the Internet


 Web Server
   Continually connected to the Internet
   Runs web server software (such as Apache or Internet
    Information Server)
   Uses HTTP (Hypertext Transfer Protocol)
   Receives request for the web page
   Responds to request and transmits status code, web page, and
    associated files




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                  1.5 Basic Internet Protocols


      Protocols : rules that describe the methods used for
       clients and servers to communicate with each other
       over a network.

      There is no single protocol that makes the Internet and
       Web work. A number of protocols with specific
       functions are needed.




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                     1.5 Basic Internet Protocols


 FTP (File Transfer Protocol)
      A set of rules that allow files to be exchanged between computers on the
       Internet.
      Web developers commonly use FTP to transfer web page files from their
       computers to web servers.
      FTP is also used to download programs and files from other servers to
       individual computers.


 E-mail Protocols
      Sending E-mail
        • SMTP Simple Mail Transfer Protocol

      Receiving E-mail
        • POP (POP3) Post Office Protocol
        • IMAP Internet Mail Access Protocol

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                 1.5 Basic Internet Protocols


 Transmission Control Protocol/Internet Protocol
  TCP/IP

      TCP/IP has been adopted as the official communication
       protocol of the Internet.
      TCP and IP have different functions that work together to
       ensure reliable communication over the Internet.




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                1.5 Basic Internet Protocols


 Transmission Control Protocol (TCP)
    Purpose is to ensure the integrity of communication
    Breaks files and messages into individual units called
     packets

 Internet Protocol (IP)
    A set of rules that controls how data is sent between
     computers on the Internet.
    IP routes a packet to the correct destination address.
    The packet gets successively forwarded to the next closest
     router (a hardware device designed to move network
     traffic) until it reaches its destination.




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                     1.5 Basic Internet Protocols


 HTTP - Hypertext Transfer Protocol
      A set of rules for exchanging files such as text, graphic images, sound,
       video, and other multimedia files on the Web.


                                        HTTP Request




                                       HTTP Response



      Web browsers send HTTP requests for web pages and their associated
       files.
      Web servers send HTTP responses back to the web browsers.



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          1.6 Technologies/Tools of the Internet


      World Wide Web: a branch of the Internet that provides
       access to hyperlinked information.

      E-mail: electronic message containing information sent
       from one computer to another over networks.

      Listservs/mailing      lists:   a    facility that       allows
       participation in ongoing discussions via e-mail.

      Usenet Newsgroups and discussion groups: world-
       wide distributed system of online discussion groups in
       which people continuously participate. Newsgroups allow
       people with a common interest to subscribe to one or
       more groups for posting, reading and replying to
       electronic mail.



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           1.6 Technologies/Tools of the Internet

      Internet Relay Chat and web chatting: having a
       conversation with many people on a variety of topics in real
       time. All the parties to the conversation are participating
       simultaneously regardless of the time zone they are in.

      Channels: Channels on the web are a pre-selected
       information source that can send information to your
       computer automatically according to a predetermined
        schedule.

      FTP: File Transfer Protocol allows you to copy files from one
       computer connected to the Internet to another computer
       connected to the Internet. It allows you to download
       information, upload web pages and transfer information
       between computers.

      Telnet: The Telnet protocol is an application that allows a
       remote connection to another computer.

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           1.6 Technologies/Tools of the Internet

      Intranet: are private networks that help an organization to
       share information between departments, units and regions
       across a network

      Internet Phone: allows one to put a number of calls on the
       same line without sacrificing sound quality.

      Video Conferencing: allows you to chat with one or more
       people in real time and/or to see live images as you speak
       or type.

      Blogs: Blogs or web logs are personal web pages that
       contain personal thoughts and links to other sites that are of
       particular interest to a blog owner.

      Wikis: Wikis are collaborative websites where the
       community participate in writing a publication, like an
       encyclopaedia or a general purpose website.

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                  1.7 World Wide Web (WWW)

             Development of the Web
                         1989-1991: Web invented by Tim Berners-Lee at
                          European Physics Laboratory (CERN).

                         1993: Marc Andreesen and others at NCSA create
                          Mosaic, a Web browser with a graphical user interface
        Bill              that could run on Windows, Macintosh, or Unix
      Clinton
                          computer.

 ”When I took office,    1994: Andreesen and Jim Clark found Netscape, and
  only high energy        create first commercial Web browser, Netscape
     physicists
  had ever heard of       Navigator.
  what is called the
     World Wide          August 1995: Microsoft introduces its version of Web
 Web... Now even my       browser, Internet Explorer.
   cat has it's own
        page.”




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               1.7 World Wide Web (WWW)

      What is WWW?
         is a way of accessing information over the medium of the
          Internet.
         is one of the major services of the internet who hosts
          information of almost about anything one might like to
          search for.
         computer network consisting of a collection of Internet
          sites that offer text and graphics and sound, video and
          animation resources through the hypertext transfer
          protocol.

      The Web uses the HTTP protocol, only one of the languages
       spoken over the Internet, to transmit data. Web services,
       which use HTTP to allow applications to communicate in
       order to exchange business logic, use the Web to share
       information.
      The Web also utilizes browsers, such as Internet
       Explorer or Firefox, to access Web documents called Web
       pages that are linked to each other via hyperlinks.
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             1.7 World Wide Web (WWW)

      Web Browsers

        a programme used to locate, display, browse and view
         information on a website.

        when you request a web page by entering the URL in
         the location field of the browser, the browser contacts
         the web server and asks for a copy of the page. The
         browser displays the page when it arrives.

        a browser can be text based in which case you would
         only be able to view web pages in text mode or could
         have a graphical user interface in which case you would
         be able to view the web page in graphical mode.



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             1.7 World Wide Web (WWW)

      Web Addresses

        Each Web page has a unique address called the
         Uniform Resource Locator (URL).

        The URL tells the computer how and where to
         look for a document.

        Example: http://www.cnn.com/world/index.html

        The hypertext links are attached to Web
         addresses.




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             1.7 World Wide Web (WWW)


      Web Pages

        A Web page is a file on the Web.

        A Web site is a collection of Web pages maintained
         by a college, government agency, company or
         individual.

        A Web page is created by using a computer
         language called Hypertext Markup Language
         (HTML).

        HTML is a set of codes used to format Web pages
         and create links.



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          1.7 World Wide Web (WWW)
      Hypertext

        Web pages are hypertext documents.

        A hypertext document is one that contains
         highlighted text or links that connect to other pages
         on the Web.
                       By clicking on the hypertext link you can
                        go to another Web page on the same
                        computer, or a Web page on a computer
                        across the world.

                       The Web uses a protocol called Hypertext
                        Transfer Protocol (HTTP) to transfer
                        documents containing hypertext.

                       HTTP's job is similar to that of TCP/IP.
                        HTTP and TCP/IP, both protocols, or
                        standards, tell computers how to
                        communicate with each other.
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Introduction to Internet and
World Wide Web


    END of CHAPTER 1




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