Communication, Networks, The

internet and the Worldwide Web

The Internet

What is a network? A collection of

computers and devices connected together via communications devices and media• Modems• Cables• Telephone lines• Satellites

message board

instant messaging

file transfer

e-mail

Web

The Internet

What are some of the services found on the Internet?

chat

p. 2.3 Fig. 2-1

Next

Goal:

To function even if part of the network

were disabled or destroyed

Became functional

in September

1969

Goal:To allow scientists at different locations to

share information and work together

on military and scientific projects

History of the Internet

How did the Internet originate?

ARPANET

Networking project by Pentagon’s

Advanced Research Projects Agency

(ARPA)

Government

Cable companies

Satellite companies

Telephone companies

History of the Internet

Who provides the structure for the Internet today?

Networks from corporations, commercial

firms, and other companies

World Wide Web Consortium (W3C)

• Oversees research and sets standards and guidelines

Internet2 (I2)

• Internet-related research and development project

• Develops and tests advanced Internet technologies

History of the Internet

Who controls the Internet? The Internet is a public, cooperative, and

independent network No single entity controls or owns the Internet Several organizations advise and define

standards

High speed connection• Employees and students• Computers part of a local area network (LAN)• Connect to service provider through a high-speed connection

line leased from local telephone company

How the Internet Works

How can you connect to the Internet?

Dial-up access• Home or small business

• Computer, modem, regular telephone line

• Dial into an ISP or OSP

Newer high-speed technologies• Home and small business

• Digital subscriber line (DSL) – provides high-speed Internet connections over regular copper telephone line

• Cable modem- provides high-speed Internet connections through cable television network

How might data travel the Internet using a telephone line connection?

Step 1Step 1Step 2

Step 1Step 2

Step 3

Step 1Step 2

Step 3

Step 4

Regional ISP

Step 1Step 2

Step 3

Step 4

Step 5

Regional ISP

National ISP

Step 1Step 2

Step 3

Step 4

Step 5

Step 6

Regional ISP

National ISP

National ISP

Internet backbone

Step 1Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Regional ISP

Local ISP

National ISP

National ISP

Internet backbone

How the Internet Works

Step 1Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Regional ISP

Local ISP

National ISP

National ISP

Internet backbone

1: You initiate an action to request data from the Internet.

2: A modem converts the digital signals from the computer into analog signals, which are understood by telephone lines.

3: Data (request) travels through telephone lines to a local ISP.

4: Data may pass through one or more routers before reaching its final destination.

5: The regional ISP uses lines, leased from a telephone company, to send data to a national ISP.

6: The national ISP routes data across the country to another national ISP.

7: Data moves from a national ISP to a local ISP and then to a destination server.

8: The server retrieves the requested data and sends it back through the Internet backbone to your computer.

How the Internet Works

What is an Internet protocol (IP) address? Number that uniquely identifies each computer or

device connected to the Internet Four groups of numbers, each separated by a period Number in each group is between 0 and 255

IP address 199.95.72.10

first part identifies network

last part identifies specific

computer

How the Internet Works

What is a domain name? Text version of an IP address Components are separated by periods Each domain name represents one or more IP

addresses

IP address 199.95.72.10

Domain name www.scsite.com

How the Internet Works

What is a top-level domain (TLD) abbreviation? Identifies the type of organization associated

with the domain Sometimes called dot com when TLD is com

Internet Corporation for Assigned Names and Numbers (ICANN)

Group that assigns and controls TLDs

How the Internet Works

What systems control domain names?

Domain name system (DNS)

System on the Internet that stores the domain names and their corresponding

IP addresses DNS server

Translates the domain name into its associated IP

address

The World Wide Web

What is the World Wide Web (WWW)? Also known as the Web A worldwide collection of electronic documents Each document on the Web is called a Web page Can contain text, graphics, sound, and video Can contain built-in connections to other documents A Web site is a collection of related Web pages

The World Wide Web

What is a Web browser? Also called a browser Software

program that allows you to access and view Web pages

Two popular browsers for personal computers• Netscape• Internet

Explorer

The activity of jumping from one Web page to another is surfing

The World Wide Web

What is surfing the Web? Links can point to an item on the same Web

page, a different Web page at the same Web site, or a separate Web page at a different Web site in another city or country

The World Wide Web

What are the parts of a URL?

protocol domain name path

http://www.nationalgeographic.com/travel/index.html

Web Publishing

Hardware

• Digital camera

• Scanner

• Sound card

• Microphone

• PC camera

What is needed for creating a Web page? Also called Web page authoring

Software to prepare HTML

• HTML (hypertext markup language)

• A set of special codes that format a file for use as a Web page

• Created with either:

• Word processing package

• Web page authoring software

Upload, or copy, the site to the

Web server

Locate a Web server to store your

site• Provided by many

ISPs and OSPs at no additional cost

• Provided by a Web hosting service for a monthly fee

Web Publishing

How do you deploy a Web site?

Apply to an official registrar

for a specific domain name

Register site with search engines

using a submission

service

• A Web-based business that helps register your site

Webmaster

Individual responsible for

maintaining a Web site and developing

Web pages

Web Publishing

What else might be needed to create a Web site?

Other Internet Services

What is e-mail? Electronic mail The transmission of messages and files via a

computer network Use an e-mail program to work with messages

create

receive

store print

sendforward

delete

Step 1Step 1

Step 2

Step 1

Step 2

Step 3

Step 1

Step 2

Step 3Step 4

How do you send an e-mail message?

Other Internet ServicesStep 1

Step 2

Step 3Step 4

Step 5

1 Start an e-mail program and point to the New Mail Message button

2 Click the New Mail Message button to display the Message window

3 Enter the recipient’s e-mail address, the subject, and the message in the Message window

4 Click the Insert File button to attach a JPG file containing a picture to the message. Locate the file on your hard disk and click its name. An icon for the file displays. Click the Send button to send the message.

5 When Sally receives the e-mail message, she opens the JPG file to view the picture.

Other Internet Services

What is an Internet e-mail address? A combination of a user name and a domain name

that identifies a user so he or she can receive Internet e-mail

user name or user-ID

A unique combination of characters that identifies you

at domain name

Identifies the mail server

mail server

The server that contains the mailboxes

Other Internet Services

How can you get e-mail? Most ISPs and OSPs provide an Internet e-mail

program and a mailbox on a mail server as a standard part of their Internet access services

Some Web sites provide e-mail services free of charge

address book

Allows you to store a list of names and e-mail addresses

mailbox

Storage location usually residing on the computer that connects you to the

Internet

Other Internet Services

file download window

What is FTP? File Transfer Protocol

An Internet standard that allows you to upload and download files with other computers on the Internet