Tài liệu Module 1: Internet Concepts pdf

Module 1: Internet
Concepts
Contents
Overview

1

Introduction to the Internet

2

Architecture of the Internet

9

Connecting to the Internet

18

Services Available on the Internet

24

Electronic Commerce

30

Web Development Technologies

31

Lab 1: Working on the Internet

36

Review

38


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Module 1: Internet Concepts

Instructor Notes
Presentation:
60 Minutes
Lab:
10 Minutes

This module provides students with an overview of the Internet. It explains the
history and the architecture of the Internet, as well as the various types of
connections and the services available on the Internet. Finally, the module
introduces students to the various Web development tools.
After completing this module, students will be able to:
!

Describe the architecture of the Internet.

!

Connect to the Internet.

!

Identify the services available on the Internet.

!

Identify the various Web development tools.

Materials and Preparation
This section provides you with the materials and preparation needed to teach
this module.

Required Materials
To teach this module, you need the following materials:
!

Microsoft PowerPoint file 1912A_01.ppt.

!

Module 1, “Internet Concepts”

!

Lab 1, “Working on the Internet”

Preparation Tasks
To prepare for this module, you should:
!

Read all of the materials for this module.

!

Complete the labs.

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Module 1: Internet Concepts

Module Strategy
Use the following strategy to present this module:
!

Introduction to the Internet
This topic provides an overview of the Internet. First, explain the need for a
global network. Then, introduce the services available on the Internet.
Finally, explain about intranets and extranets.

!

Architecture of the Internet
This topic explains the architecture and working of the Internet. First,
explain the need for protocols. Then, explain the need for addresses and the
various types of addresses. Finally, describe the client/server architecture of
the Internet.

!

Connecting to the Internet
This topic describes how a client computer connects to a Web server. First,
describe online services. Then, explain what Internet service providers are.
Finally, describe the various types of Internet connections possible.
Highlight the differences between each of the connection types. Spend more
time on DSL, a new technology.

!

Services Available on the Internet
This topic describes the services available on the Internet. Explain each
service and its purpose.

!

Web Development Tools and Technologies
This topic covers various Web development tools. First, explain markup
languages. Then, describe scripting languages. Finally, explain the COM
technologies.


Module 1: Internet Concepts

# Overview
Slide Objective

To provide an overview of
the module topics and
objectives.

!

Introduction to the Internet

Lead-in

!

Architecture of the Internet

!

Connecting to the Internet

!

Services Available on the Internet

!

Electronic Commerce

!

Web Development Technologies

!

Lab 1: Working on the Internet

!

Review

In this module, you will learn
about the Internet, the
services available on the
Internet, the architecture of
the Internet, and how to
connect to the Internet. You
will also learn about
electronic commerce and
the Web development tools
and technologies.

In the past few years, the Internet has become a vast source of information,
connected millions of people and businesses worldwide, and made
communications simple and quick through the use of e-mail and online
chatting.
The Internet is an association of thousands of networks and millions of
computers that are connected together to share information.
After completing this module, you will be able to:
!

Describe the architecture of the Internet.

!

Identify various ways to connect to the Internet.

!

Identify the services available on the Internet.

!

Identify the various Web development tools.

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Module 1: Internet Concepts

# Introduction to the Internet
Slide Objective

To provide an overview of
the Internet.

Lead-in

In this section, you will learn
about the history of the
Internet. You will also learn
about the various services
available on the Internet.

!

What is the Internet?

!

Services Available on the Internet

!

Intranets

!

Extranets

The Internet was created about 30 years ago with the simple objective of
allowing disparate computers to communicate with each other. Today, the
Internet has grown into a vast resource for information and communication. It is
the single largest network of computers with a host of available services.
Other types of networks include intranets and extranets. An intranet utilizes the
same protocols as the Internet and provides many of the same services, such as
e-mail and Web pages. However, an intranet is for use within an organization
and access to the information on an intranet is restricted to the employees of a
given organization. An extranet is like an intranet except that it allows limited
access to users outside the intranet.


Module 1: Internet Concepts

3

What Is the Internet?
Slide Objective

To explain the need and
evolution of the Internet.

!

Internet:
$

Lead-in

The Internet is an expansive

network of computers and a
cost-effective mode of
communication between two
places across the globe.

$

$

$
$

!

A global network of computers
Allows one node to communicate with any other node
through various paths
Currently consists of many small and large networks of
computers
A vast resource of information
Provides popular services, such as the WWW, e- mail,
chat rooms, and news

History of Internet
$

ARPAnet, NSFnet

The Internet is a global network of linked computers. When you connect to the
Internet, your machine is simply another node on this global network. The

topology of the Internet is like a web, allowing any node to communicate with
any other node through various paths.
The history of the Internet goes back to 1969 when the Advanced Research
Projects Agency (ARPA) of the U.S. government started a project to link
computers. The main objective of this network of computers was to enable
research scientists at the Department of Defense to communicate with each
other. The network was named ARPAnet.
The participation of educational institutions—including Harvard University, the
University of California, Massachusetts Institute of Technology, and Stanford
University—ensured the addition of more computers and the growth of
ARPAnet. Over a period of time, the size of the network increased and more
organizations started adding their own networks to ARPAnet.
By 1980, the traffic on ARPAnet had increased tremendously. As a result, the
National Science Foundation created a nationwide network called the NSFnet.
Consequently, ARPAnet was withdrawn from the service.
The purpose of NSFnet was to provide high-quality computing services to the
public across the country. NSFnet became the launch pad for the Internet.
The Internet currently consists of more than 1,300,000 small and large networks
of computers and continues to grow at a rapid rate. With more than 50 million
Web pages containing an average of 500 words per page, the Internet is the
single largest pool of information.
The Internet has become a vast resource of information. It provides services
catering to sports, entertainment, education, news, and current affairs and
various other categories. The most popular services on the Internet are the
World Wide Web, electronic mail, chat rooms, and newsgroups.


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Module 1: Internet Concepts

Services Available on the Internet
Slide Objective

To highlight the popular
services available on the
Internet.

!

WWW (HTTP)

Lead-in

!

E-Mail (SMTP)

!

Chat Rooms (IRC)

!

Newsgroups (NNTP)

!

FTP (FTP)

The Internet is growing at a
phenomenal rate. This is
because the Internet
provides information to a
worldwide audience. In
addition, the Internet obtains
information with no barriers
in space or time.

The Internet has undergone major developments since its inception. These
include the number and availability of Internet connections, the advent of
powerful software to access information on the Internet, and the adoption of
universal standards. Consequently, the Internet has become a medium in its
own right, offering a host of services.

WWW
WWW is an abbreviation for World Wide Web, which is often simply referred
to as the Web. Many people confuse the Internet with the Web. The Web is a
subset of the Internet. The underlying protocol for the Web is Hypertext
Transfer Protocol (HTTP).

E-Mail
E-mail is an electronic messaging service available on the Internet. E-mail has
brought a radical change in communications across the globe. Whenever you
send a piece of e-mail, your computer's e-mail software, or e-mail client,
interacts with the Simple Mail Transfer Protocol (SMTP) server to send the email message.

Chat Rooms
Online discussions, or "chat rooms," enable the exchange of written messages
over the Internet.

Newsgroups
Newsgroups are a means of public discussion on the Internet. They function in
the same way as e-mail, but are read by millions of people worldwide. The
messages in newsgroups are presented in the form of a list known as a thread.
These messages are stored on a news server. This service uses the Network
News Transfer Protocol (NNTP) as the protocol.


Module 1: Internet Concepts

FTP
File Transfer Protocol (FTP) is a remote-access service used to exchange files
between two computers on a network.
You will learn more about these services later in this module.

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Module 1: Internet Concepts

Intranets
Slide Objective

To provide an overview of
intranets.

!

Intranet:
$

Lead-in

$

Intranets are private
networks within companies.

$

$

!

$

Ask students to explain the
difference between an
intranet and the Internet.

Provide information that is of use to the employees of a
company
Are suitable for high bandwidth services, such as video
conferencing
Can also contain sensitive and proprietary information

Working of Intranets

$

Delivery Tip

Is a smaller version of the Internet

The client forwards the request to the server
The server processes the request and sends the requested
data to the client

An intranet is an internal version of the Internet. Intranets typically provide
information that is of use to the employees of a company, such as online forms
and vacation policies. Information about benefits, a forum to share ideas on
various projects, and resource scheduling are just a few examples of ways to
use an intranet. Because the nodes of an intranet typically have higher speed
connections, intranets are suitable for high-bandwidth services, such as video
conferencing. Because they are accessible only to authorized users, intranets
can also contain sensitive and proprietary information.

Working of Intranets
Intranets use the client/server architecture and are based on the Internet
protocols. The client forwards the request to the server. The server processes
the request and sends the requested data to the client. Security measures such as
firewalls are required to block access from unauthorized sources.
Note A firewall allows people on an internal network to access the Internet,
but prevents people on the Internet from accessing the internal information.


Module 1: Internet Concepts

Extranets
Slide Objective

!

To provide an overview of
extranets.

Lead-in

Extranets are similar to
intranets; however they can
be accessed by authorized
people outside the
company.
!

Extranets
$

Exchange data with other companies

$

Share information with vendors and suppliers

$

Access services provided by other companies

$

Share news of common interest with partner companies

$

Coordinate with other companies on joint ventures

Security Features
$

Firewalls

$

Web Server Security

$

Certification Authority

An extranet is a company intranet that is accessible to users outside the
company, such as vendors, customers, and suppliers. Because part of the
intranet is made available to users outside the company, an extranet requires
special security measures.
An extranet allows you to:
!

Exchange data with other companies.

!

Share information and news with vendors and suppliers.

!

Access services provided by other companies.

!

Share news of common interest with partner companies.

!

Coordinate with other companies on joint ventures.

Working of Extranets
Extranets allow various levels of access depending on the user. To access an
extranet, you need to have a valid username and password.

Security Features
Security is a major concern in private networks such as intranets and extranets.
Some security features are listed below:
!

Firewalls
A firewall is a software security system that blocks access to an internal
network from the Internet. All the sites that require security are placed
within the firewall.

!

Web server security
Web server security uses username and password authentication. To log on
to an extranet, the user needs to enter the username and password.

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Module 1: Internet Concepts
!

Certification authority
Certification authority uses a digital certificate. The access is provided to
users based on their certificate. The certificate is an evidence of their digital
identity.


Module 1: Internet Concepts

# Architecture of the Internet
Slide Objective

To describe the architecture
of the Internet.

Lead-in

In this section, you will learn
about the architecture of the
Internet. You will also learn
about intranets and
extranets.

!

Protocols

!

Addressing Schemes

!

Practice: Obtaining the IP Address of a Server

!

Client/Server Architecture

The Internet is a network of computers with clients and servers. The primary
function of the Internet is to route the network traffic between computers.
When you connect to the Internet, your computer is only aware of the nodes
that are close to it. For example, when you try connecting to the Microsoft®
site, your computer does not know which path on the Internet will connect your
computer to the Microsoft site. Instead, your computer knows which is its
closest gateway and forwards the request to it. This gateway might not be able
to connect your computer to the Microsoft site, but it can forward the request to

another gateway that does. Gateways are network points that perform the
function of an entrance to another network. Gateways involve the use of
routers. A router determines the next network point to which a packet, or block
of data, should be forwarded towards its destination. A router is connected to
two networks and selects a route to send information. The choice is based on its
current understanding of the state of the networks to which it is connected. If
your machine is unable to connect to the Internet, the problem may be that it
does not know a gateway to which it can send the request.

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Module 1: Internet Concepts

Protocols
Slide Objective

!

To list the various Internet
protocols.

Lead-in

Protocols are a set of rules
for communication.

!

TCP/ IP
$

Protocol used for all communication on the Internet

$

Is a two-layered program, TCP and IP

Hyper Text Transfer Protocol (HTTP)
$

!

Set of rules for exchanging files, such as text, graphics,
still images, sound, and moving images

File Transfer Protocol (FTP)
$

Used to exchange files between computers on the
Internet

$

Can be used to download or upload files

$

Also runs on top of TCP/IP

A protocol is a set of communication rules. It is a set of standards that ensures
various network programs work together. Protocols exist at several levels in a
telecommunication connection.
There are three Internet protocols:
!

TCP/IP

!

HTTP

!

FTP

TCP/IP
TCP/IP, developed by the Department of Defense, is used to connect different
networks. TCP/IP is the underlying protocol that is used for all communication
on the Internet.
TCP/IP is a two-layered program. The upper layer, Transmission Control
Protocol (TCP), manages the assembling of a message or file into smaller
packets that are transmitted over the Internet and received by a TCP layer that
reassembles the packets into the original message. The lower layer, Internet
Protocol (IP), handles the address part of each packet, ensuring that it reaches
the right destination. Each gateway computer on the network checks this
address to see where to forward the message. Even though some packets from
the same message are routed differently than others, they will be reassembled at

the destination.


Module 1: Internet Concepts

11

Hypertext Transfer Protocol (HTTP)
HTTP is a set of rules for exchanging files, such as text, graphics, still images,
sound, and moving images, on the Web. HTTP is a protocol that rides on top of
TCP/IP. The Web browser is an HTTP client that sends requests to the server.
When the user enters a URL or clicks a hyperlink, the browser builds an HTTP
request. The browser sends the request to the IP address indicated by the URL.
The destination server receives the request and the requested file is returned to
the browser after it is processed.

FTP
FTP is used to exchange files between computers on the Internet. FTP can be
used to download or upload files. FTP also runs on top of TCP/IP.


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Module 1: Internet Concepts

Addressing Schemes
Slide Objective

!

To list the addressing
schemes available on the
Internet.

Lead-in

With millions of computers
connected to the Internet,
each computer needs a
unique address so that other
computers can locate the
correct information.

!

!

Server Addresses
$

Uniquely identifies a specific computer

$

Example - 131.107.1.240

Resource Addresses
$

The first section corresponds to a protocol

$

The second section corresponds to an IP address

$

Example - />
E-Mail Addresses
$

Must be unique

$

Example -

With more than a million computers and tens of millions of people logged on to
the Internet, there is an obvious need to find and direct data over the Internet.
Internet addresses help you locate the information you need as well as send
messages to the correct location. There are three types of Internet addresses:
!

Server addresses

!

Resource addresses

!

E-mail addresses

Server Addresses
The address that is used at the machine level to uniquely identify a specific
computer is called the Internet protocol (IP) address. An IP address consists of
four sets of numbers, called octets, which are separated by periods, such as
131.107.1.7 or 131.107.1.240.
However, when you browse the Web, you do not enter server addresses.
Generally, you use something much more intuitive and easy to remember, such
as www.microsoft.com. When you type www.microsoft.com in the Address
text box of your browser window, your browser contacts a Domain Name
Server (DNS). The purpose of a DNS is to map the human-readable domain
names to IP addresses. Once your browser has obtained the address, it uses this
number to contact the machine. A DNS can be compared to a telephone book.
For example, when you want to call John Smith, you first have to look John
Smith up in the phone book. Once you have obtained the phone number for
John Smith, you can place the call. All the computers on the Internet are
divided into two categories based on either an organization type or a geographic
location.


Module 1: Internet Concepts

13

Organizational domains describe the type or purpose of the organization. The
following table describes some of the common domain names.
Domain

Description

COM

Commercial organizations

EDU

Educational institutions

GOV

Government agencies

MIL

Military organizations

NET

Major network support centers

Organizational domains are continually changing, and there are likely to be
many more domain names types in the future.
Geographic domains are two-letter codes, such as US for the United States, and
CA for Canada. The following table lists some country codes.
Code

Country

AR

Argentina

AU

Australia

BE

Belgium

BR

Brazil

FR

France

DE

Germany

To connect to a resource, such as a Web page on the Internet, you can specify
either the IP address or the domain name of the computer that contains the
resource. The domain name of the computer on the Internet is passed to a
domain name server. The server reads the IP address of the target computer. It
substitutes the IP address for the user-friendly name. As an example, here are
two addresses that refer to the same server:

!

www.microsoft.com

!

207.68.156.49

Note The person who registers the domain name is responsible for choosing
the appropriate organizational category and the classification system. Most
domains in the United States use the organizational naming method. Domains
in other countries use the geographic method. The Internet Network
Information Center (InterNIC), under contract to Network Solutions, handles
the registration of domain names.

Delivery Tip

Describe the procedure for
obtaining a domain name for
an organization.

! Obtain a domain name for an organization
1. Obtain an IP address from an Internet Service Provider. The IP address will
come from a block of addresses that are allocated to the provider.
2. Submit this IP address, as well as the domain name you want, and the
technical and billing information to InterNIC.
If the domain name is available, InterNIC assigns it to the user.


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Module 1: Internet Concepts

After a domain name is assigned, users can move their Web pages from host to
host by notifying InterNIC. Within a few days of notification, DNS servers all
over the world are updated to reflect the new IP address assigned to the domain
name.
An individual or a small company may only need one IP address. However,
large companies need blocks of IP addresses and established subdomains. For
example, microsoft.com is a domain name, and home.microsoft.com is a
subdomain of the main Microsoft domain.

Resource Addresses
The Web has become a popular place for storing and displaying all manner of
information that can be accessed by individuals all over the world. The standard
Web address is called a Uniform Resource Locator (URL).
Here is an example of a URL:
/>The first section of a URL corresponds to the protocol of the service you are
using, such as HTTP or FTP. The second section of a URL corresponds to a
DNS address that is translated into a numeric IP address when a request is sent.
In the example above, the subdomain name www appears immediately before
the logical domain name, msn.com, in the URL. The owner of the domain can
change the subdomain name. The subdomain name reflects the domain server
that is dedicated for a service. For example, www.microsoft.com,
moli.microsoft.com, and ftp.microsoft.com are within the domain of
microsoft.com, but are on different subdomain servers.
The information to the right of the domain name in the address
is the path on the server for that
particular file. This path is similar to the path for a file on a personal computer.
If the path is omitted, the server provides a default response based on the

protocol used. For example, the default response to an HTTP request is to send
the file named Index.htm or Default.htm. Usually, you can specify the default
response in the server setup.
Note Some URLs are case-sensitive. The first section of the URL
is not case-sensitive, but the path and the file name
information may be case-sensitive on some operating systems, such as UNIX. If
a URL does not work, verify that you typed it in the same case as it was
provided.

E-Mail Addresses
Once you understand the concept of domain names, understanding an e-mail
address is relatively easy. The organizations that have a LAN and use internal
e-mail create e-mail names based on a naming convention. For example, you
use your first name and last initial, or firstname_lastname. The address must be
unique within the organization.


Module 1: Internet Concepts

15

If your organization connects the LAN to the Internet, the organization registers
a domain name such as MyCompany.com. Then, your Internet e-mail address is
your organization e-mail address combined with the domain name of your
organization, such as:


If your Internet access is provided through an Internet service provider (ISP) or
an online service, the domain name in the e-mail address is the domain of the
ISP or online service.

There are numerous online search and directory services to help you find e-mail
addresses.
Note If you choose to integrate Internet Explorer 5.0 with your desktop, the
Find People command is added to the Find submenu on the Start menu. You
use this command to search directory services for an e-mail address or a
physical address or phone number.
To search for an e-mail address, go to any of the following sites:
!



!



!



!



!



!

/>

Note The file names on some early model computer systems are casesensitive. When you type the filename, always type exactly the case in which
you receive them.


16

Module 1: Internet Concepts

Practice: Obtaining IP Addresses
Slide Objective

To introduce the practice.

Lead-in

In this practice, you will
obtain the IP address of a
server.

In this exercise, you will use the ping and ipconfig utilities to obtain IP
addresses.
Delivery Tip

For this exercise, provide
students with a computer
name that they can ping.

! Use the ping utility
1. On the Start menu, point to Programs, then point to Accessories, and then
click Command Prompt.

2. At the command prompt, type ping <machine name> and press ENTER.
Notice the IP address of the machine.

! Use the ipconfig utility
1. Open the Command Prompt.
2. Run ipconfig with the parameter all. Type ipconfig/all, and then press
ENTER.
Notice the information under your IP configuration. It lists the Host name, DNS
servers, and other configuration information.
Also, notice the information on the IP address, subnet mask, and the default
gateway under the adapter information.
The ipconfig diagnostic command displays all the current TCP/IP network
configuration values. With no parameters, ipconfig displays all of the current
TCP/IP configuration values, including IP address, subnet mask, and WINS and
DNS configuration.