Transcript The Internet Basics - Doral Academy Preparatory

Internet Basics
 Lesson 15-1 What Is the Internet?
 Lesson 15-2 How the Internet Works
 Lesson 15-3 Comparing Internet Services
Lesson 15-1 What Is the Internet?
Objectives
 Compare and contrast LANs, WANs, and the
Internet.
 Describe how the three main parts of the
Internet work together.
 Explain the advantages and disadvantages of
the organization of the Internet.
Key Terms: • Internet • Internet client
The Internet Connects the World No matter where you are on the planet,
chances are good that the Internet is there, too. An international
communication and information system, the Internet connects millions of
computers and people.
People use the Internet at school, at work, and at home. At school,
students and teachers use the Internet to do research and share
information. At work, people use it to send e-mail, share files, and
communicate with co-workers near and far. At home, people use the
Internet to get help with homework, play games, and shop, among other
activities.
The Internet has changed the way people around the world live and work.
It is considered one of the most important and exciting inventions in
history.
Organization of the Internet
The Internet is a vast network that links
together millions of computers around the
world. It runs 365 days a year, 24 hours a
day.
Structure of the Internet
 Two or more computers connected to one another
are known as a network of computers. Computers
linked together in the same building, such as a
school, are called a local area network (LAN).
Computers or LANs that are linked together over a
large area, such as different parts of the country, are
called a wide area network (WAN).
 The Internet is a global WAN, a network of networks.
It connects everything from single computers to large
networks. The Internet can even connect computers
that run different operating systems. This ability to
share information with almost any computer makes
the Internet a powerful tool for communication.
Structure of the Internet
Servers: The Internet is made up of three
important parts: servers, clients, and
protocols.
Internet servers are the computers that
provide services to other computers by way of
the Internet. These services include
processing e-mail, storing Web pages, or
helping send files from one computer to
another.
Structure of the Internet
Clients and Protocols Internet clients are the
computers that request services from a server.
When you connect to the Internet, the computer
you use is considered a client. Protocols are the
special sets of rules that allow clients and
servers to connect to one another. Protocols tell
computers how to format data and transmit it
over a network.
Inventing the Internet
In the 1960s, people were working on ideas that later
became the Internet. In 1969, the first four major
computer centers in the United States were linked. By
1973, the network was international.
In 1983, the Internet protocols went online for the first
time. Two major groups worked on the development of
The Internet: the United States military and university
researchers.
Inventing the Internet
United States Military In the 1960s, the United States government
wanted to find a way to communicate in the event of a
disaster or military attack. The military began to work on a system
that would operate even if some communication connections
were destroyed. The Defense Advanced Research Projects
Agency (DARPA) of the U.S. Department of Defense focused on
computer networking and communications. In 1968, this
research led to a network of connected computer centers called
the Advanced Research Projects Agency Network (ARPANET).
Inventing the Internet
University Researchers With the military's leadership
and funding, DARPA formed computing research
centers at universities across the United States. From
1969 through 1987, the number of computers on the
network increased from four to more than 10,000.
These connections created the networks that became
the Internet.
Internet Management
Who owns the Internet?
The truth is, no specific organization or government
does. The Internet is made up of many networks.
Each network is managed by an organization, school,
company, or government. So, although each part of it is
managed, no one is in charge of the entire Internet. This
provides both opportunities for growth and problems.
Freedom of the Internet
One advantage to the open quality of the
Internet is the ability to share information.
Because much of the Internet is available for
public use, there is a lot of freedom to get
information from the Internet as well as to add to
it.
 Anyone can make an idea or opinion
accessible to anyone else.
Is this good or bad?
Pitfalls of the Internet
However, there are pitfalls to this open organization. People can
post whatever point of view or information they want, even if it can
sometimes be misleading or false. It is up to the users of the
Internet to think critically about the information they find. If you have
a question about anything you find on the Internet, ask an adult you
trust about it.
Because the Internet is not managed and protected by a specific
government or agency, each individual has to figure out
how to best use it. The network developed from the ideas of the
U.S. military and university researchers has now become a global,
open system of communication and information.
Lesson 15-2 How the Internet Works
Objectives
 Identify ways to connect to the Internet.
 Compare and contrast Internet Service Providers
and online services.
 Summarize the need for protocols.
 Distinguish between Internet Protocol addresses and
domain names.
Key Terms: • Internet service provider (ISP) • username
• online service • navigate • Transmission Control Protocol/Internet
Protocol (TCP/IP) • Internet Protocol (IP) address
• domain name system
Accessing the Internet
There are different ways to connect to the
Internet. The reasons for various options are
availability, location, speed, and price.
1. Dial up
2. DSL
3. Cable
4. Satellite
Accessing the Internet
Dialup, ISDN, and DSL Access The least expensive way to get online is to use a
dialup connection between a standard phone line and a modem. These connections
are called "dialup“ because your computer must connect to the Internet by using a
telephone number to contact a server. When the session is over, the connection is
broken. Some Digital Subscriber Lines (DSL) require a special telephone line.
Integrated Services Digital Network (ISDN) lines require a special ISDN adapter
and modem. As a result, both services cost more than regular phone service.
Cable and Satellite Cable television companies offer Internet access through cable
modems. This access is at speeds much faster than dialup modems. You need a
network card in your computer, a cable modem, and cable access. Satellite access
Is also very fast for downloading files to your computer, but it requires a phone line
and a modem for sending files to outside users.
Getting Online
After you have access to the Internet, you must
select a way to get online. Choices include
Internet service providers and online services.
Internet Service Providers An Internet service Provider (ISP) is a
company that provides a link from your computer to the Internet. For a
fee, an ISP provides its subscribers with software, a password, an
access phone number, and a username. A username identifies who
you are when you access the Internet. An ISP does not guide you
through the Internet—it only provides an easy-to-use connection to it.
You can use either a local ISP or a national TSP.
Getting Online
Online Services: An online service connects your computer to
the Internet. Online services are businesses that provide tools
to help you navigate, or move to different parts of, the Internet.
Online services are not the Internet. They provide special software
that you load onto your computer. The software makes the
connection to the service, which then guides you through content
and activities. Three popular online services are America
Online (AOL), Microsoft Network® (MSN), and Yahoo®.
Protocols
The Internet provides a way to link a single
computer or smaller networks to a larger
network. To transfer data from network to
network, a set of standards, or protocols, is
used to define how things should work.
Protocols determine how networked computers
communicate, format data, and transmit data.
Protocols
Internet Protocols Internet protocols are
referred to as
Transmission Control Protocol/Internet
Protocol or TCP/IP.
TCP defines how one Internet-connected
computer contacts another and exchanges
information.
IP defines the Internet addresses.
IP Addresses
Each computer that connects to the Internet has to be
uniquely identified. To do this, every computer is
assigned a four-part number separated by periods
called the Internet Protocol (IP) address.
For example, the IP address for your computer might be
123.257.91.7. The administrator of the network to which
your computer connects assigns your IP address.
Domain Names
IP addresses can be difficult to remember, so a simpler naming system
called the domain name system using letters as well as numbers was
created. A domain name identifies one or more IP addresses. If you want
to obtain a domain name, you or your ISP can contact a registering
organization. It then contacts an organization called InterNIC, which keeps
the master database of domain names.
How do domain names work? Let's say you want your computer to
access information stored on another computer. Your local ISP's domain
name server will contact the domain name server you are calling. The
information to identify both computers will be exchanged, and the contact
will be made.
Every domain name has an ending, or suffix, that indicates which type of
organization registered the name. The following table lists these suffixes—
called top-level domains—and the types of organizations they represent.
Top-Level Domain
Lesson 15-3 Comparing Internet
Services
Objectives
 Identify and describe kinds of Internet
services.
 Summarize how to access information
on the Web.
 Analyze the usefulness of e-mail in daily
living..
Key Terms: • Web browser • portal • search engine • hypertext •
hyperlink • uniform resource locator (URL)• download
• upload
Internet Services
When you send an e-mail message to a friend,
you use one kind of Internet service. Browsing
the World Wide Web is done through another
type of service. Different Internet services are
used for accessing the World Wide Web,
sending and receiving electronic mail, and
conducting file transfers.
Internet Services
Intranets
The Internet uses protocols that define how
the client software and server software communicate. In
the same way, some organizations have their own
networks of services, called intranets, which are private.
Employees can use e-mail, the Web, and other Internet
technologies with their company's intranet. Intranets,
however, are used within a company and are not open
to the public.
Internet Software
The protocols for delivering an e-mail message are not the same
as the protocols for displaying a Web page. Typically, there is
different software for each Internet service. You use a Web
Browser to view Web pages. The two most popular Web browsers
are Safari® and Microsoft Internet Explorer. You use a mail
program to send and receive e-mail messages. This distinction,
however, is beginning to vanish. Hotmail's Outlook Web
Access, for example, uses a Web site to access and send e-mail.
Internet Software
Portals
Internet portals provide organized subject guides to Internet
content. They usually offer search engines as well. A search
engine is software that finds and lists information that
meets a specified search. First, the search engine asks you to
type a keyword into a blank field. Then, the search engine will
give you the results of that search. Popular search engines
include Yahoo!, Excite, and InfoSeek.
Accessing Information on the World
Wide Web
The World Wide Web is a huge collection of hypertext documents
called Web pages. In a hypertext document, certain words or
Pictures can serve as hyperlinks. A hyperlink is a link to another
document on the World Wide Web.
Hyperlinks Usually hyperlinks appear underlined, in a different
color, or highlighted. Sometimes there are buttons or images
that can be clicked. When you move your mouse over a hyperlink,
the pointer changes to an icon of a hand. You can click this
hyperlink item to be transferred to another document.
Accessing Information on the World
Wide Web
URLs
When you click a hyperlink, the Web browser
retrieves and displays the document connected to that
hyperlink.
How does this work? Every document has a
unique address, called a uniform resource locator
(URL), which tells exactly where the document is
located on the Internet. A hyperlink instructs the
browser to go to the URL for that document.
Electronic Mail
For many Internet users, electronic mail, or e-mail, has replaced traditional
mail and telephone services. E-mail is fast and easy. If you organize your
e-mail addresses into groups, you can broadcast, or send, a message to a
group in just one step.
E-mail Pros and Cons E-mail is not free, and it's not instantaneous.
However, you do not pay to send each e-mail, as you would a letter. The
cost of your e-mail service is included in the fee you pay your Internet
service provider or online service provider. In most cases, it takes minutes
or more for an e-mail message to reach its destination. But it costs the
same and takes approximately the same amount of time to send a
message to someone in your own city as it does to send a message
halfway around the world.
Transferring Files
File Transfer Protocol (FTP) lets you transfer files on the Internet. With an
FTP client, you can transfer files from an FTP server to your computer in
an operation called downloading. In uploading, you transfer files from the
client to the server.
FTP can transfer both text files and binary files. Binary files are program
files, graphics, pictures, music or video clips, and documents. Once you've
stored a file on an FTP server, you can distribute the URL so that your
friends can also download the file from the server.
One difference between using an FTP server and e-mail to transfer files is
that with FTP, the file stays on the server until you take it off. With e-mail, a
file that has been transferred will be lost once the e-mail message has
been deleted. E-mail is considered a more secure method, however,
because only the recipient of the e-mail message has access to the
attached files.
An e-mail message may travel a long way from
the sender to the receiver.