The Internet

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The Internet

• Computing
• Andrea Carlin.

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Introduction

• What is the Internet ?
• The Internet is a world wide collection of
  networks that are connected to each other and
  function as a single co-operative virtual
  network.

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Origins

• The Internet started with the ARPANET.
• This was a research network developed by the
  Advance Research Projects Agency of the US
  Department of Defense.
• This experimental military network was designed
  to function even during partial disruptions
  caused by bomb attacks.
• The network software decided which route the
  network traffic would take, depending on the
  availability of various parts of the network.

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• A need developed for all university departments
  to have a network, so BITNET (Because Its Time
  Net) was set up.
• The Internet originally reached most
  universities, government research labs and
  military installations in over 40 countries.
• Today the reach of the Internet is universal

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Internet Today

• Estimates of traffic growth on the Internet
  indicate that it is growing at 15-20 a month.
• The most highly developed part of the Internet is
  in North America where it was originally
  developed.
• Currently, about 100 million hosts are connected
  to the Internet, with 25 located in Europe.
• The Internet is not owned by any one country or
  organization, its a network of networks from all
  individual countries.

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Personal Access to the Internet

• A service provider will provide you with your
  personal account in order to gain access to the
  Internet.
• As well as an account, you will require
• A personal Computer
• A Modem
• A phone line for dial up access
• A Web browser and dial-up software.
• A Service Provider will supply a package that
  includes software instructions, passwords, etc..

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• You must load this software onto your PC and
  connect to the service provider with a modem.
• The Service Provider will then connect you to the
  Internet at the cost of a local call.
• This is the most economical way of using the
  Internet as you will only be visibly on the
  Internet on a part-time basis (late in the
  evenings / weekends).
• If the volume of traffic justifies it, an
  Internet Service Provider can also provide a
  permanent Internet connection via a separate line
  /ISDN line. This is the most expensive type of
  Internet access for individual users.

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Corporate Access to the Internet

• Connecting to the Internet internally within an
  organization will require access to a
  PC/workstation that is connected to a corporate
  host machine or server using a network card.
• Your organization network will in turn be
  connected to either another similar organizations
  network or a service provider which will provide
  access to the Internet.
• You also need Web browser software.
• Using corporate access, you can permanently
  connect to the Internet and you are visible on
  the Internet to others.

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Uses for the Internet

• Traditionally the Internet was for research,
  scientific collaboration and for electronic mail.
• Today, it is used for business and many other
  purposes as well.
• The most common uses are
• Putting information on the WWW / Advertising.
• Exchanging electronic mail (email).
• Research purposes.
• Shopping.
• News distribution and access ( news groups).
• Groupware communication.

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• Increasingly today, you can use the Internet for
  business.
• Some of the more recent uses of the Internet
  include on-line radio stations, for making
  telephone calls, video conferencing and
  multimedia exchange.
• Shopping on the Internet has grown significantly.
  The big advantage here is that it can offer
  lower cost sales.
• Also, it has international reach and can provide
  a wide variety of goods to suit all tastes.
• Different methods of preventing credit card fraud
  are being introduced by banking authorities.

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Access Methods provided by Eircom

• Basic Telephone line
• Integrated Services Digital Network line
• Dedicated Leased line
• Broadband

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Internet Applications
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Common Internet Applications

• Today, with the significant growth of Internet
  users, a wide variety of specialized Internet
  application exist. For example,
• Web browsers
• Search Engines
• Intranets /Extranets
• Firewalls
• Virus Detection

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Web Browsers

• A web browser is an important piece of software
  that enables you to browse the Internet.
• Two most popular browsers are Microsofts
  Internet Explorer and Netscapes Communicator.
• Through your browser, you request your favorite
  search engine, then type your request, and the
  search engine responds in seconds, listing many
  Web sites that have information on the subject
  you requested.
• Listings which are usually highlighted and
  underlined in blue are called hyperlinks.

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• The browser is a program that displays certain
  files on the Internet in an accessible, and
  visually attractive way using Hypertext Markup
  Language (HTML).
• A URL (Uniform Resource Locator) is displayed in
  the Address bar, at the top of the browser
  window.
• The URL describes the location of the file your
  browser is displaying.
• A hyperlink is a visual element on a Web page,
  that loads a specified URL into the browser
  widow.
• The URL usually begins with the letters http//
  which stands for HyperText Transfer Protocol.

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• HTTP is an Internet protocol (a form of language)
  that enables the distribution of hypertext
  documents.
• Web servers allows you to surf content over the
  Internet using HTTP.
• The web server accepts HTTP requests from
  browsers like Internet Explorer 5 and returns
  appropriate HTML documents, images, video etc...

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• Other client-server protocols for the Internet
  include
• File Transfer Protocol (FTP)
• News Network Transfer Protocol (NNTP)
• Simple Mail Transfer Protocol (SMTP)
• To conclude, an Internet browser offers numerous
  control which are easy to use, making it an
  attractive method to surf the net. As well as
  bringing you information, you can also download
  elements of a Web page, including its code and
  any graphical element that appear on that page.