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Tutorial 1
Introduction to the Internet and the
World Wide Web
History, Structure, and
Getting Connected
New Perspectives on The Internet, Fifth Edition—
Comprehensive, 2005 Update Tutorial 1
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Objectives
• Obtain an overview of the information and
tools that are available on the Internet
• Learn what computer networks and internets
are and how they work
• Find out how the Internet and the World Wide
Web began and grew
• Compare different methods for connecting to
the Internet
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Internet and World Wide Web:XP
Amazing Developments
• The Internet is a large collection of computers all over
the world connected to one another.
• One of the most amazing technological developments
of the 20th century.
• The World Wide Web is a subset of computers on the
Internet that has helped make Internet resources
available to people who are not computer experts.
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Internet and World Wide Web:XP
Amazing Developments
• New Ways to Communicate
 E-mail
 Electronic discussions
 Instant messaging
• Information Resources and Software




Newspapers & magazines
Government documents
Research reports & books
Software download sites
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Internet and World Wide Web:XP
Amazing Developments
• Doing Business Online
 Electronic storefronts
 Coordinate worldwide operations
 Recruit employees
• Entertainment
 Review restaurants, movies, theater, musical
events and books.
 Interactive games
 Follow sports teams
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Computer Networks
• Network Interface Card (NIC): a card used to connect
a computer to a network of other computers.
• Server: computer that accepts requests and shares
some or all of its resources with computers it is
connected to.
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Client/Server Local Area Networks
• Server: runs software that coordinates information
flow among other computers.
• Client: computers connected to a server.
• Network Operating System: software that runs on a
server.
• Client/Server Networks: one server computer
sharing its resources with multiple client computers.
• Local Area Network (LAN): network of computers
located close to each other.
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Client/Server LAN
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Client/Server Local Area Networks
• Node or network node: each computer,
printer, or other device connected to a
network.
• Minicomputer and mainframe computer:
larger, more expensive computers used by
businesses and organizations to process
large amounts of work.
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Connecting Computers XP
to a Network – Types of Cable
• Twisted Pair: oldest type, used by telephone companies,
usually Category 1.
• Coaxial Cable: 20 times faster than Category 1, more
expensive
• Category 5: carries signals between 10 & 100 times
faster than coaxial cable, easy to install.
• Fiber-optic cable: most expensive, transmits pulsing
beams of light through very thin strands of glass, fastest
transmission rate.
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Types of Cable
TWISTED-PAIR
COAXIAL
FIBER-OPTIC
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Connecting Computers XP
to a Network – Wireless Networks
• Becoming more common as costs continue to drop.
• Welcome in organizations that occupy old buildings.
• Popular with companies whose employees use
laptop computers.
• Used by schools in classrooms, libraries, and study
lounges.
• Used in homes.
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Wireless Home Network
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Wide Area Networks
• WAN: a network of networks or an internet.
• Internet: a worldwide collection of
interconnected networks; owners have
voluntarily agreed to share resources and
network connections.
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Origins of the Internet
• Early 1960s by the U.S. Department of Defense (DOD).
• Major research project authorized as a part of national
security.
• Explored ways to connect large mainframe computers and
weapons installations distributed all over the world.
• Defense Advanced Research Projects Agency (DARPA)
charged with the task
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Connectivity: Circuit SwitchingXP
vs Packet Switching
• Circuit switching:
 centrally controlled
 single-connection method
 used by most local telephone traffic today
• Vulnerable to destruction of signal control
point or any link in the single path that carries
the signal.
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Connectivity: Circuit SwitchingXP
vs Packet Switching
• Packet-switching: files and messages broken down
into packets and labeled electronically with codes for
their origin and destination.
• Packets travel from computer to computer along the
network until they reach their destination.
• Routers determine the best way for a packet to move
towards its destination.
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Connectivity: Circuit SwitchingXP
vs Packet Switching
• Routers use routing algorithms programs to
determine best path for packets.
• Packet-switched networks more reliable:
 rely on multiple routers instead of central point of
control.
 each router can send individual packets along different
paths if parts of the network are not operating.
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Origins of the Internet
• DARPA researchers connected first computer switches
in 1969.
• ARPANET grew over next three years to include over
20 computers.
• Computers communicated to other computers on the
network by using Network Control Protocol (NCP).
• Protocol: collection of rules for formatting, ordering,
and error-checking data sent across a network.
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Open Architecture Philosophy
Four Key Points:

Independent networks should not require any internal
changes to be connected to the Internet.

Packets that do not arrive at their destinations must
be retransmitted from their source network.

The router computers do not retain information about
the packets they handle.

No global control will exist over the network.
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Open Architecture Philosophy
• New set of protocols developed in 1970 by Vincent
Cerf and Robert Kahn:
 Transmission Control Protocol
 Internet Protocol
 (TCP/IP)
• TCP: rules used by computers on a network to
establish and break connections.
• IP: rules for routing of individual data packets.
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Open Architecture Philosophy
• TCP/IP used today in LANs and on the Internet.
• Term Internet first used in a 1974 article about the
TCP protocol written by Cerf and Kahn.
• Vincent Cerf considered to be the father of the
Internet by many.
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Birth of E-Mail:
A New Use for Networks
• Ray Tomlinson, an ARPANET researcher, wrote a
program that could send and receive messages over
the network in 1972.
• E-mail was born and rapidly became widely used in
the computer research community.
• ARPANET continued to develop faster and more
effective network technologies.
• Began sending packets by satellite in 1976.
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More New Uses for
Networks Emerge
• File Transfer Protocol (FTP) - transfer files between
computers.
• Telnet - users log in to their computer accounts from
remote sites.
• Mailing lists (LISTSERV), information posting areas
(Usenet), and adventure games among new
applications appearing on the ARPANET.
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Interconnecting the Networks
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Commercial Interest Increases
• National Science Foundation (NSF) prohibited
commercial network traffic on networks it funded.
• Businesses turned to commercial e-mail services.
• Larger firms built TCP/IP-based WANs that used leased
telephone lines to connect field offices to corporate
headquarters.
• NSF permitted two commercial e-mail services, MCI
Mail and CompuServe, to establish limited connections
to the Internet in 1989.
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Commercial Interest Increases
• Intranet: LANs or WANs that use TCP/IP protocol but
do not connect to sites outside the firm.
• Extranet: an intranet that allows selected outside
parties to connect.
• Internet Engineering Task Force (IETF): a selforganized group that makes technical contributions to
the engineering of the Internet and its technologies.
• ARPANET grew from 4 computers in 1969 to over
300,000 by 1990.
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Growth of the Internet
• Formal definition of Internet
was adopted in 1995 by the
Federal Networking Council
(FNC).
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From Research Project to
Information Infrastructure
Growth in number of Internet hosts
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Growth of the Internet
• Number of hosts connected to Internet includes only
computers directly connected to the Internet.
• Internet traffic now carries more files that contain
graphics, sound, and video, so Internet files have
become larger.
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New Structure for the Internet
• Organized around four network access points
(NAPs), operated by four different telecommunications companies.
• The four companies and their successors sell access
to the Internet through their NAPs to organizations
and businesses.
• The NSFnet still exists for government and research
use.
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New Structure for the Internet
• More than 180 million connected host computers and
more than 700 million worldwide Internet users.
• TCP/IP numbering system that identifies users on the
Internet is running short of numbers.
 IP version 4 provides a maximum of about 4 billion
addresses.
 IP version 6 approved in 1997 by the IETF allows existing
users to continue accessing the Internet while new system is
being implemented.
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New Structure for the Internet
• The Internet has become one of the most amazing
technological and social accomplishments of the
century.
• Computers linked to this interconnected network are
located in almost every country of the world.
• Billions of dollars change hands every year over the
Internet.
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World Wide Web
• World Wide Web: a way of thinking about
information storage and retrieval.
• Web: software that runs on some of the computers
connected to each other through the Internet.
• Two important innovations played key roles:
 hypertext
 graphical user interfaces (GUIs)
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Origins of Hypertext
• 1945: Vannevar Bush speculated engineers would
eventually build a machine that would store a
person’s books, records, letters, and research results
on microfilm. Mechanical aids would help retrieve.
• 1960: Ted Nelson described similar system where
text on one page links to text on other pages. He
called it hypertext.
• 1960’s: Douglas Engelbart created first experimental
hypertext system on one of the large computers.
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Hypertext and Graphical UserXP
Interfaces Come to the Internet
• Hypertext Markup Language (HTML): a language
that includes a set of codes (or tags) attached to text.
• Hypertext Server: a computer that stores files
written in HTML; other computers connect to it and
read files.
• Hypertext Link (hyperlink): points to another
location in the same or another HTML document.
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Hypertext and Graphical UserXP
Interfaces Come to the Internet
• Web Browser: software that lets users read HTML
documents and move from one HTML document to
another through hypertext link tags in each file.
• HTML: a subset of Standard Generalized Markup
Language (SGML).
• SGML: has been used by organizations for many years to
manage large document-filing systems.
• GUI (graphical user interface): a way of presenting
program output using pictures, icons, and other graphical
elements.
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Hypertext and Graphical UserXP
Interfaces Come to the Internet
• Mosaic: first GUI
program to read HTML
and use HTML
documents’ hyperlinks to
navigate from page to
page on computers
anywhere on the Internet.
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The Web and Commercialization
of the Internet
• Businesses quickly recognized profit-making potential
offered by a world-wide network of easy-to-use
computers.
• The Netscape Navigator Web browser was an instant
success.
• Internet Explorer Web browser entered the market
soon after Netscape’s success became apparent.
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Growth of the World Wide Web
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Connection Options
• NAPs (network access points) offer connections to
large organizations and businesses.
• Those businesses provide Internet access to other
business and individuals as ISPs.
• Internet service providers (ISPs) provide
customers with software to connect to the ISP,
browse the Web, send and receive e-mail messages,
and perform other Internet-related functions.
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Hierarchy of Internet Service Providers
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Connection Bandwidth
• Bandwidth: amount of data that can travel through a
communications circuit in one second.
• Bandwidth depends on the type of connection ISP
has to the Internet and the kind of connection you
have to the ISP.
• Available bandwidth for any type network connection
between two points is limited to narrowest bandwidth
that exists in any part of the network.
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Connection Bandwidth
• Bandwidth measured in bits per second (bps).
• When you extend your network beyond a local area,
the speed of the connection depends on type of
connection used.
• POTS (or plain old telephone service) is one way to
connect computers or networks over longer
distances.
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Connection Bandwidth
• Digital Subscriber Line (DSL): higher grade of service
offered by some telephone companies.
• Integrated Services Digital Network (ISDN): first
technology developed using a DSL protocol; offers
bandwidths up to 256 Kbps.
• Asymmetric Digital Subscriber Line (ADSL): offers
transmission speeds ranging from 16 Kbps to 9 Mbps.
• T1 or T3 connections: often used by businesses and
large organizations; much more expensive than POTS or
ISDN connections.
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Connection Bandwidth
• Internet 2: operated by group of research universities and
the NSF; has backbone bandwidths greater than 10 Gbps.
• Cable connection: increasingly available in the U.S.; can
deliver up to 10 Mbps to an individual user.
• Satellite connection: appealing to users in remote areas;
can download at a bandwidth of approximately 400 Kbps.
• Fixed-point wireless connections: offered by some
companies
 technology similar to wireless LANs
 limited and more expensive.
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Connecting Through Your
School or Employer
• Many universities and community colleges offer Internet access
to their students, faculty members, and other employees.
• Your employer might offer you a connection to the Internet
through the computer you use in your job.
• Most schools and employers have an acceptable use policy
(AUP) that specifies the conditions under which you can use
their Internet connections.
 possibly least expensive option
 should carefully consider if limitations placed on use of the
Internet are greater than the benefits
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Connecting Through an
Internet Service Provider
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• Reliable connectivity at a reasonable price.
• Terms of AUPs usually less restrictive.
• Offer modem connections to individuals and higher
speed connections to businesses. May also offer DSL
connections to individual and business customers.
• Quality of service may deteriorate significantly over
time if ISP adds many new customers without
expanding bandwidth.
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Connecting Through a
DSL Provider
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• Connections increasingly available in the U.S. and a
few other countries.
• Significantly faster connection that dial-up service.
• Speeds and subscription rates similar to cable
modems.
• Sometimes long delays in installation and repair
services.
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Connecting Through Your
Cable Television Company
• Cable modem converts digital signals into radio-frequency
analog signals similar to television transmission signals.
• Signals travel over the same lines that carry cable television
signals.
• Cable connection can provide very fast downloads to your
computer from the Internet (up to 170 times faster than a
telephone line connection).
• Greatest disadvantage for most people is that cable connection
is not available in all areas.
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Connecting by Satellite
• Satellite Internet connections may be only option
available in rural areas.
• Speeds and monthly fees similar to those of cable
and DSL providers.
• Installation fee usually considerably higher because
the dish must be installed and aimed at the satellite.
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Summary
• The Internet and the Web began in the military and research
communities.
• The Internet and the Web have become an important worldwide
infrastructure.
• The Internet and the Web support many resources through one
of the most powerful communication tools the world has ever
known.
• There are a number of options for connecting your computer
and the computers of businesses and other organizations to the
Internet.
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