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Internet & E-mail Day 1

Internet & E-mail Day 1. Computer Networks. Two or more computers can be connected together and it’s called as computer network. Computer Network: Computers Peripherals (Network Printers). Advantages of a Computer Network. Resource Sharing Data sharing File sharing Software Sharing

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Internet & E-mail Day 1

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  1. Internet & E-mailDay 1

  2. Computer Networks • Two or more computers can be connected together and it’s called as computer network. • Computer Network: • Computers • Peripherals (Network Printers)

  3. Advantages of a Computer Network • Resource Sharing • Data sharing • File sharing • Software Sharing • Hard disk capacity sharing • Avoid data duplication Centralized databases • Implementation of network software systems

  4. Classification of Computer Networks • Local Area Networks (LAN) • Computer network spread in limited geographical area Eg. Department Network Class room Network Office Network Head Office Network Colombo City Network

  5. Classification of Computer Networks • Wide Area Networks (WAN) • Wide spread computer network Eg. HSBC Network World Bank Network BBC Network DHL Network Air Line Reservation Network Internet

  6. Internet • WAN of WAN’s • Six million computers • ARPANet (Advanced Research Project Agency) to Internet • Number of Services • World Wide Web • Email • Telemedicine • Video Conferences • Internet Relay Chat

  7. Internet Connection • Dial-up Network • Dedicated Line/ Leased Line • ADSL • ISDN • VSAT

  8. Dial-up Network Internet Service Provider/ ISP MODEM Public Switch Telephone Network/ PSTN MODEM Computer

  9. MODEM • MOdulation • Conversion of Analog signal to Digital signals • PSTN to Computer in user end • DEModulation • Conversion of Digital signals to Analog signals • ISP to PSTN • PSTN transfers analog signals

  10. Dedicated/ Leased Line Internet Service Provider/ ISP DSU Public Data Network/ PDN DSU Computer

  11. DSU/ Digital Service unit • DSU converts unipolar digital signals to bipolar digital signals • If transferring of unipolar digitals signal to long distance causes energy wasting and low signal levels • PDN transfers bipolar digital signals to long distances

  12. Internet Service Providers/ ISP • Provides internet connections to clients • Sri Lanka Tele Com • Lanka Internet • Dialog GSM • Lanka Bell • Eureka

  13. Creating Dial-up Network • Start button, Control Panel menu item • Internet Options, Connection tab, Setup button • Next, Connect to the Internet Option, Next • Setup my connection manually option, Next’ • Connect using a dial up modem, Next • ISP Name (Provided by ISP), Next • Phone number (Provided by ISP), Next • User name, password, confirm password, Next • Add shortcut on desktop, Finish button • Use shortcut and connect to internet

  14. After Connecting to the Internet Notification Area

  15. Web Browsers • Application software which display web pages at client end • Web pages written by Hyper Text Markup Language/ HTML • Examples to web browsers • Internet Explorer (Microsoft) • Netscape Navigator (Netscape)

  16. Web Designing/ Static Web Pages Web Server Static Web Pages Web Browser Server Client

  17. Web Developing/ Dynamic Web Pages Web Server Static Web Pages CGI Programs Dynamic Web Pages Department Database Web Browser Server Client

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