Networking BASICS

1
Networking BASICS

• The Internet and Its Tools
• Unit 3
• Lesson 10

2
Objectives

• Recite a brief history of the Internet.
• Tell how the Internet works.
• Explain how to use a Web browser, e-mail, a
  listserv, a newsgroup, and search tools.
• Create a document using HTML.

3
The Internet

• It is not controlled or managed by one person or
  group.
• Anyone can connect to the Internet.
• There is no control regarding what can be posted.

4
History

• The U.S. was concerned that foreign nations may
  attack.
• A computer network was needed that could
  withstand an attack.
• The Internet was modeled after the interstate
  highway system.

5
History

• ARPANET was launched in 1969 to link 4 sites.
• TCP/IP allowed multiple computers to connect to
  each other.
• It was replaced by NSFNET in the 1980s.
• Hypertext Transport Protocol and browsers opened
  up the Internet to anyone.

6
Domain Name System (DNS)

• It resolves (or finds) a Web sites IP number
  when given its name.
• It is a database organized as a hierarchy.
• It is organized into 3 different levels.
• DNS is distributed at multiple locations.

7
Domain Name System (DNS)
8
Web Browsers

• They allow users to view text, data, pictures,
  animation, and video.
• A Web page contains instructions to a browser
  about how to display items.
• Microsoft Internet Explorer is the most popular
  browser.

9
E-Mail

• It is the most common Internet tool.
• They are either character-based or use a
  graphical user interface.
• Documents are sent as attachments.
• File compression software reduces the size of
  attachments.

10
Listserv

• It is also called a discussion list.
• It is an extension of an e-mail distribution
  list.
• Users subscribe and automatically receive copies
  of all e-mail messages.
• Listserv address Address of the automated
  mailing program.

11
Listserv Etiquette

• Spend time reading before responding.
• Use a descriptive Subject heading.
• Include part of the original message when
  replying.
• Use upper- and lowercase.

12
Newsgroup

• Questions and answers are posted in a central
  location.
• It is not necessary to save or sort e-mail
  messages.
• It may require special software of the client.

13
Newsgroup
14
Portals

• Portals are also known as an online service.
• Portals are ready-made menus of lists of
  information.
• Each selection narrows choices until the
  information is located.

15
Search Engine

• The spider reads the Web pages and stores
  information in an index.
• The search engine sifts through the index to find
  the users requests.
• The ranking of pages is important.

16
Search Engine
17
Hypertext Markup Language (HTML)

• It is the standard way of defining how text and
  graphics are displayed.
• The browser reads HTML document instructions.

18
Hypertext Markup Language (HTML)

• Each page is made up of elements.
• The elements are indicated by tags.
• A tag is lt, tag name, gt.
• The ending tag contains a slash.
• ltHTMLgt . . . lt/HTMLgt

19
Summary

• The Internet is not just one large computer
  network it is an internation-al network of
  computer networks. These networks are of
  different shapes and sizes and are scattered all
  across the world. The network that was the
  foundation of the Internet dates back to the
  1950s. The U.S. government created an agency
  within the Department of Defense called ARPA
  (Advanced Research Projects Agency). ARPAs job
  was to make the U.S. the world leader in science
  and technology. In 1962, the government
  commissioned a study to determine how the
  military could maintain command and control over
  its missiles after an attack occurred. ARPA was
  given the task of designing a computer network
  for the military, later to be called ARPANET. In
  1981, another nation-wide network, NSFNET, was
  built for those colleges that did not have access
  to ARPANET. By the early 1990s, most networks
  were leaving the slower ARPANET and linking to
  NSFNET, which was then called the Internet.

20
Summary (continued)

• One of the key elements of how the Internet works
  is the Do-main Name System (DNS). The role of the
  DNS is to look up a Web sites IP number when
  given its name. The DNS is a data-base, organized
  as a hierarchy (or tree), of the name of each
  site on the Internet and its corresponding IP
  number. Instead of being on only one computer,
  the DNS database is divided and distributed to
  many different servers on the Internet, each
  being responsible for different areas of the
  Internet.

21
Summary (continued)

• A number of different tools are used for
  accessing information on the Internet. A Web
  browser lets a user view text, data, pic-tures,
  animation, and video on the Internet by using a
  graphical user interface. Prior to Web browsers,
  users were forced to memorize and type in long
  character-based commands. The most common tool
  used on the Internet is e-mail. A variety of
  e-mail packages are available. Modern e-mail
  packages have a graphical user interface and are
  accessible through a Web browser. Documents sent
  along with e-mail messages are known as
  attachments. Many users turn to file compression
  software, which reduces the size of an attachment
  by compress-ing the file. This software looks for
  patterns of characters in the file and
  substitutes a single symbol for a string of
  characters.

22
Summary (continued)

• A listserv is an automated way to send e-mail to
  a group. Users subscribe and unsubscribe to a
  listserv list. When an e-mail message is sent to
  the list, the listserv program automatically
  copies the incoming message and sends it to the
  e-mail address of each person in the group. The
  listserv program takes care of all of these tasks
  so users do not have to create and maintain
  distribution lists. A newsgroup allows users to
  post questions and answers in a central location
  instead of sending them direct-ly to each member.
  One of the advantages of a newsgroup is that all
  messages are stored in one central location,
  meaning that the user does not have to save
  individual e-mail messages. Also, a newsgroup
  makes it easy to follow a discussion thread.

23
Summary (continued)

• There are two basic types of search tools. The
  first is searching an online service, or portal.
  Portals provide ready-made menu lists of
  information from which users can select. These
  lists may include sports, education, food,
  health, and a wide range of other topics. Another
  type of search tool is a search engine which
  automatically searches the Internet and compiles
  a data-base that can be searched quickly by a
  user.
• Hypertext Markup Language (HTML) is the
  underlying founda-tion of all Web pages. HTML is
  a standard way of defining how text, pictures,
  and graphics should appear on a Web page. HTML is
  interpreted by a Web browser, which displays the
  con-tent based on the instructions, or tags,
  contained in the HTML document. An HTML Web page
  is made up of elements, and these are defined by
  the use of tags.