Using the Internet

1
Using the Internet
2
Objectives

• Learn about the many systems that use the
  Internet for communication.
• Examine the organization of the Internet
  infrastructure.
• Investigate Internet service providers, and learn
  how to select one.

3
The Internet and Systems That Use It

• The Internet is many networks connected together,
  all of which use the same method of
  communication.
• The beginnings of the Internet occurred in 1969
  when the Advanced Research Projects Agency
  (ARPA), charged with developing an internet work
  that could withstand nuclear attacks on the
  United States, connected two university networks
  to create a network called the Advanced Research
  Projects Agency Network (ARPANET).

4
The Internet and Systems That Use It (Continued)

• A protocol is a language or a set of rules for
  communication, and the Internet uses many
  different protocols in many different situations.
• The Internet is a public network made up of
  hundreds of thousands of private networks that
  can also communicate using these same protocols.
• These private networks that use the same
  protocols, standards, and equipment as the
  Internet are called intranets.

5
The World Wide Web

• The World Wide Web (WWW or W3) is a collection of
  interconnected information that is stored on
  computers all around the world.
• A Web browser is software designed to display
  files available on the Web to the user.
• Most of the information on the World Wide Web is
  stored in files that are formatted using
  Hypertext Markup Language (HTML).
• Essentially, HTML is a set of codes that are
  included in the text describing how the text
  should be displayed or printed.

6
The World Wide Web (Continued)

• Files that include HTML code are called
  hypertext, hypertext files, hypertext documents,
  Web pages, or simply pages.
• Web communication and standards of HTML are
  controlled and monitored by the World Wide Web
  Consortium (W3C), an organization made up of
  private, educational, and governmental
  organizations from around the world.
• The software that receives the request from the
  browser is called a Web server, and the computer
  that is running the Web server is called a server.

7
The World Wide Web (Continued)

• A Web site is a group of Web pages and related
  text, databases, graphics, audio, and video files
  that are served up by a Web server to present
  information.
• The first publicly available Web browser that
  could display graphics was Mosaic, released in
  1993 by the National Center for Supercomputing
  Applications (NCSA) at the University of
  Illinois.
• Today, the most popular Web browser is Microsoft
  Internet Explorer, distributed by Microsoft.

8
Using Web Browsers

• A URL (Uniform Resource Locator) is an address
  for a Web page file or other resource on the
  Internet.
• The first part of the URL stands for Hypertext
  Transfer Protocol.
• http// www.csudh.edu/cis275/first.htm

9
Using Web Browsers (Continued)

• Domain names are easy for humans to remember and
  use, but the devices on the Internet rely on
  numeric addresses to identify every host on every
  network that is connected directly to the
  Internet.
• Such a numeric address is called an IP address
  (Internet Protocol address).
• A group of controlling protocols is called TCP/IP
  (Transmission Control Protocol/Internet
  Protocol), and sometimes is called a protocol
  stack.

10
Microsoft Internet Explorer

• Microsoft Internet Explorer was first introduced
  in October 1995, and is included in Windows XP
  and other Windows operating systems.
• Some people still use earlier versions of the
  software because of the overhead associated with
  the later versions.
• Overhead is the amount of system resources
  required by the software to function, such as
  space on the hard drive and computing power.

11
Microsoft Internet Explorer (Continued)

• Internet Explorer is holding the Web pages in a
  temporary Internet folder on your hard drive
  called a cache, and can display them without
  having to go back to the Web server to download
  again.

12
AutoComplete Feature

• Internet Explorer keeps track of the URLs you
  enter in the Address bar.
• Internet Explorer also keeps track of data you
  enter in data-entry forms on Web pages, to make
  it easy for you to reenter the same data at a
  later time.
• To customize AutoComplete, follow the directions
  for Windows XP as illustrated on pages 10 and 11
  of the text.

13
Saving Files on the Web to a Floppy Disk or Hard
Disk

• Sometimes, its helpful to save a Web page to a
  floppy disk or a folder on your hard drive other
  than the browser cache folder.
• To save a Web file on a floppy disk, use the
  directions on pages 14 and 15 of the text.
• Also follow the directions on page 15 when you
  want to view a page that you previously saved to
  a floppy disk.

14
Limiting the Content Available to a Browser

• Internet Explorer 5 and higher versions support
  the World Wide Web Consortiums specifications
  for content selection, called the Platform for
  Internet Content Selection (PICS).
• These specifications allow parents and other
  responsible individuals (such as employers and
  educators) to limit the content available to a
  browser.
• PICS is a voluntary rating system in which Web
  developers assign their site a rating based on
  language, nudity, sex, and violence.

15
Introducing HTML

• HTML is a subset of the Standard Generalized
  Markup Language (SGML), a standard developed in
  1986 to retain formatting and linking information
  in a document as it is moved from one computer or
  software application to another.
• An HTML file is sometimes called hypertext, a
  hypertext file, a hypertext document, a Web page,
  or a page.
• A tag is special HTML or SGML code in a text file
  that controls how certain parts of the text are
  to be formatted.

16
Introducing HTML (Continued)

• Some possible formatting options include
  boldface, underlining, and indentations.
• A tag is read by, or interpreted by, the browser
  as it displays an HTML page.
• Tags also can be used as links to point to other
  Web pages.

17
Web Pages Built with Frames

• Frames allow a Web site designer to display
  different information in two or more separate
  areas of the screen.
• More than one Web page can be displayed on the
  same screen, each in its own frame.

18
Hyperlinks

• A Web page often contains a text or graphic that
  you can click to jump to some other place in the
  same document or to a different Web page.
• This text or graphic is called a hyperlink, a hot
  link, or simply a link.

19
Search Engine Web Sites

• Search engine Web sites are devoted to the
  purpose of helping users find information
  anywhere on the Web.
• A subject directory gets its information from
  someone manually entering the data into a
  database.
• A spider search engine searches Web sites all
  over the Web to get information for its database.

20
Search Engine Web Sites (Continued)

• A meta search engine gets its information from
  databases on other search engine sites.
• A spider search engine gets data by using
  automated search engine software called a spider,
  robot, or a Web crawler.
• This software independently searches the entire
  Web for keywords in Web sites.

21
Search Engine Web Sites (Continued)

• Meta tags are tags that contain information about
  the Web page content.
• Meta tags can include information about the
  author of the Web page, the software used to
  build it, the date and time it was built,
  information used by PICS, and so forth.
• A meta tag included on the page specifically for
  a spider or Web robot to find and use is called a
  meta robot tag.

22
Searching an Individual Web Site

• The Web site show in Figure 1-18 includes a
  Search box.
• This Search box might link to another Web site,
  but many times a search utility searches only the
  current site.
• Several ways to search a site are summarized in
  the following list.
• Find Static index Full text index
• Site map Keyword index

23
Search Engines

• A search engine is used as a software application
  to search for words in documents or in a
  database.
• A search engine like Google at www.google.com is
  used by hundreds of thousands of people everyday
  to find useful information on the Web.
• Google has quickly become the most popular search
  engine on the Web.

24
Using Search Boxes Effectively

• When using search utilities on the Web, knowing
  how to use Search boxes effectively can make your
  work easier.
• The expressions AND, OR, NOT, and NEAR can be
  used to narrow a search and the keywords lost,
  link, title, and image can make your searches
  more powerful.
• Table 1-2 lists explanations and examples of each.

25
Evaluating Good Design

• The following list describes some guidelines to
  use when evaluating the overall design of a Web
  site.
• The very best Web sites are shortcuts.
• The Web site should create the feeling of
  community.
• Web sites should have a user-friendly home page
  that loads quickly, gets the users attention,
  and clearly presents what is found on the site.
• The remainder of this list appears on page 30 of
  the text.

26
Web Sites That Help You Evaluate and Design Web
Sites

• Some Web sites that can help you evaluate other
  sites and design your own site are
• builder.com.com by CNET
• www.developer.com by Earth Web
• www.wpdfd.com by Joe Gillespie
• www.colin.mackenzie.org by Colin Mackenzie
• The list is continued on page 30 of the text.

27
Sending and Receiving E-Mail

• E-mail is a method for sending a text message or
  a file to an individual or group of individuals
  via the Internet.
• Internet e-mail addresses have three parts the
  user name, the _at_ symbol, and the name of the mail
  server that receives and then delivers the
  message.
• E-mail consists of four components the sending
  client, sending server, receiving server, and
  receiving client.

28
Chat Rooms

• A chat room is a data communications link that
  several people share for text transmissions in
  real time.
• Real-time communication occurs when people type
  messages to each other and instantly receive a
  response.
• Chat rooms use an application called Internet
  Relay Chat (IRC), originally written by Jarkko
  Oikarinen, that, like e-mail and the World Wide
  Web, uses the client/server method.

29
Chat Rooms (Continued)

• Another real-time communication technology called
  instant messaging is based upon the chat room
  concept.
• Instant messaging does not use IRC, but instead
  uses proprietary software that users must install
  onto their computers.

30
Newsgroups

• A newsgroup is a service on the Internet or on a
  private network that allows a group of people to
  post articles and respond to those articles, so
  information can be shared among the members of
  the group.
• A newsgroup can be private or public.
• It might have a subscription fee, such as the
  newsgroups of ClariNet, a commercial newsgroup
  organization whose main contributor is United
  Press International.

31
Newsgroups (Continued)

• An ISP can subscribe to ClariNet for a fee, and
  then can control access to this newsgroup.
• Another example of a newsgroup service is Usenet,
  which consists of thousands of free newsgroups
  that circulate over the Internet.
• Usenet is the most popular newsgroup service.

32
A Brief History of the Internet

• The Internet came into existence in 1969 when
  Advanced Research Projects Agency (ARPA)
  connected the computers of four major
  universities in the United States (UCLA,
  Stanford, UC Santa Barbara, and the University of
  Utah).
• Until the late 1980s, it was a loosely organized
  group of interconnected networks that were used
  predominantly by major academic institutions in
  the United States for research and development.

33
A Brief History of the Internet (Continued)

• In 1986, the National Science Foundation (NSF)
  formed its network called NSFnet to connect five
  of these major academic institutions, which were
  spread from the East Coast to the West Coast New
  York, New Jersey, Pennsylvania, Illinois, and
  California.
• Because NSFnet connected smaller networks to each
  other, it was called a backbone network.

34
Network Access Points (NAPs)

• A NAP is a major Internet connection point that
  is used to connect and route traffic between
  smaller commercial backbones.

35
Internet Service Providers (ISPs)

• An Internet service provider (ISP) is a business
  that provides connectivity to the Internet.
• ISPs can be a small business that provides
  connectivity in only one city, or a large company
  with access points in many cities and countries.

36
Services Offered by an ISP

• The primary purpose of an ISP is to provide
  access to the Internet.
• To connect to the Internet, a computer needs a
  physical connection to the ISP, software to
  communicate over the Internet, and an address so
  others on the Internet can identify the computer.
• To connect to an ISP, a computer must be using an
  operating system that supports the communication
  protocol of the Internet, which is TCP/IP.

37
Services Offered by an ISP (Continued)

• Windows XP, Windows 2000, Windows 98, Windows 95,
  Windows Me, Windows NT, Linux, and the Macintosh
  operating system all support TCP/IP.
• The final thing needed to connect to the Internet
  is an Internet address so the computer can be
  identified on the Internet.

38
Ways to Connect to an ISP

• Regular telephone lines are the most common way
  for an individual to connect to an ISP.
• In addition, two competing high-speed methods are
  available.
• Both were introduced to the marketplace at about
  the same time, cost about the same, and attain
  about the same speeds.
• These two methods are DSL lines and cable modems.

39
How an Internet Service Provider Works

• After you connect to an ISP by cable modem, DSL,
  or telephone line, the ISP connects you to the
  Internet.
• The ISPs equipment can be very simple or
  complex, depending on the ISPs size.
• Figure 1-36 shows an example of how a small ISP
  might connect to the Internet.
• A local area network (LAN) is a group of
  computers and other devices networked together
  that is confined to a small area, such as one
  building.

40
How an Internet Service Provider Works (Continued)

• A router is a device that connects two or more
  networks and can intelligently make decisions
  about the best way to route data over these
  networks.
• The two networks in Figure 1-36 are the ISPs LAN
  and the regional ISPs network.
• This regional network is an example of a wide
  area network (WAN), a network that covers a large
  geographical area and might use a number of
  communications technologies.

41
How an Internet Service Provider Works (Continued)

• Before data gets onto a T1 line, it must be
  cleaned and formatted by a device called a
  CSU/DSU, which is really two devices in one.
• The Channel Service Unit (CSU) acts as a safe
  electrical buffer between the LAN and a public
  network accessed by the T1 line.
• A Digital Service Unit or Data Service Unit (DSU)
  ensures that the data is formatted correctly
  before its allowed on the T1 line.

42
How an Internet Service Provider Works (Continued)
43
What You Can Expect from an ISP

• An ISP is expected to offer access to the World
  Wide Web, e-mail services, and possibly FTP
  services.
• Some offer chat room and newsgroup services, as
  well as some space for a personal Web site.

44
Point of Presence

• A small ISP might have only local telephone
  number that you can dial for access, but some
  larger ISPs have local telephone numbers in many
  major cities and other countries.
• A POP (point of presence) is a connection point
  to the Internet, either a telephone number you
  can call to access your ISP or an IP address
  provided by your ISP.

45
Performance, Price, and Service

• It goes without saying that performance, price,
  and service are three important factors to
  consider when selecting an ISP
• An ISP should have a technical support desk
  available in the evenings, on weekends, and on
  holidays.
• Another important service is the ability to
  access your e-mail from a Web site in the event
  you need to check your mail from someone elses
  computer.

46
Summary

• The Internet is a group of networks that encircle
  the entire globe.
• The client/server concept works like this Client
  software on one computer requests information
  from server software that is on another computer.
• Web pages are written as hypertext documents
  using HTML, and are transmitted on the Internet
  using HTTP.
• A search engine is software used to search a Web
  site, a group of sites, or the entire World Wide
  Web.

47
Summary (Continued)

• A Web search site such as Google gets its
  information by spiders or robots that search Web
  sites.
• Most individuals and small companies use an
  Internet service provider (ISP) to connect to the
  Internet by way of regular telephone lines, DSL
  lines, or cable modems.
• An ISP most often provides e-mail, World Wide
  Web, chat room, newsgroups, and FTP services.