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Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Chapter 2: Technology Infrastructure: The Internet and the World Wide W=
eb
Electronic Commerce, Seventh Annual Edition
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Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
2
Objectives
• In this chapter, you will learn about:&#=
13;
• The orig=
in,
growth, and current structure of the Internet
• How
packet-switched networks are combined to form the Internet
<=
/span>
• How Inte=
rnet
protocols and Internet addressing work
• The hist=
ory
and use of markup languages on the Web, including SGML, H=
TML,
and XML
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Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
Objectives (continued)
• How HTML
tags and links work on the World Wide Web
• The
differences among internets, intranets, and extranets
<=
/div>
• Options =
for
connecting to the Internet, including cost and bandwidth factors&=
#13;
• Internet2
and the Semantic Web
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Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
The Internet and the World Wide Web
• Computer
network
– Any
technology that allows people to connect computers to each other&#=
13;
• The Inte=
rnet
– A large
system of interconnected computer networks spanning the glo=
be
• World Wi=
de
Web
– A subset=
of
computers on the Internet
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
Origins of the Internet
&#=
8226; Early
1960s
– U.S. Department of Defense funded research to <=
/span>explore
creating a worldwide network
&#=
8226; In
1969
&#=
8211; Defense
Department researchers connected four computers into a network
called ARPANET
&#=
8226; Throughout
the 1970s and 1980s
&#=
8211; Academic
researchers connected to ARPANET and contributed to its
technological developments
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
New Uses for the Internet
&#=
8226; 1972
&=
#8211; E-mail
was born
&#=
8226; Mailing
list
&#=
8211; E-mail
address that forwards any message <=
/span> received
to any user who has subscribed to the list
•
– Started by a group of students and programmers =
at
Duke University and the University of North Carolina
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
Growth of the Internet
• In 1991,=
the
NSF:
– Eased
restrictions on commercial Internet activity
– Began
implementing plans to privatize the Internet
• Network
access points (NAPs)
– Basis of=
the
new structure of the Internet
• Network
access providers
– Sell Inte=
rnet
access rights directly to larger customers and indirectly to
smaller firms and individuals through ISPs
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
Emergence of the World Wide Web
• The Web&=
#13;
– Software
that runs on computers connected to the Internet
• Vannevar =
Bush
speculated that engineers would eventually build a memory
extension device (the Memex)
• In the
1960s, Ted Nelson described a similar system called hypertext
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
10 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Emergence of the World Wide=
Web
(continued)
R=
26; Tim
Berners-Lee developed code for a hypertext server program<=
span
style=3D'mso-spacerun:yes'>
&#=
8226; Hypertext
server:
&#=
8211; Stores
files written in the hypertext markup language
&=
#8211; Lets
other computers connect to it and read files
&#=
8226; Hypertext
Markup Language (HTML)
&=
#8211; Includes
a set of codes (or tags) attached to text
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Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
11 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Packet-Switched Networks
• Local ar=
ea
network (LAN)
– Network of
computers located close together
• Wide area
networks (WANs)
– Networks=
of
computers connected over greater distances
• Circuit&=
#13;
– Combinati=
on
of telephone lines and closed switches that connect th=
em
to each other
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
12 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Packet-Switched Networks <=
/span>(continued)
• Circuit
switching
– Centrally
controlled, single-connection model
• Packets&=
#13;
– Files and
e-mail messages on a packet-switched network are broken down =
into
small pieces, called packets
– Travel f=
rom
computer to computer along the interconnected networks u=
ntil
they reach their destinations
•
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
13 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Routing Packets
• Routing
computers
– Computers
that decide how best to forward packets
• Routing
algorithms
– Rules
contained in programs on router computers that determine the best p=
ath
on which to send packets
– Programs
apply their routing algorithms to information they have sto=
red
in routing tables
•
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
14 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
15 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Internet Protocols
• Protocol
– Collectio=
n of
rules for formatting, ordering, and error-checking data sent acros=
s a
network
• Rules for messa=
ge
handling include:
– Independ=
ent
networks should not require any internal changes to be connected =
to
the network
– Packets =
that
do not arrive at their destinations must be retransmitted from th=
eir
source network
– Router
computers act as receive-and-forward devices
– No global
control exists over the network
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
16 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
TCP/IP
• TCP
=
– Controls
disassembly of a message or a file into packets before transmiss=
ion
over the Internet
– Controls
reassembly of packets into their original formats when they reach t=
heir
destinations
• IP
=
– Specifies
addressing details for each packet
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
17 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
IP Addressing
&#=
8226; Internet
Protocol version 4 (IPv4)
– Uses
a 32-bit number to identify computers connected to the
Internet
&#=
8226; Base
2 (binary) number system
&#=
8211; Used
by computers to perform internal calculations
=
&#=
8226; Subnetting
– Use
of reserved private IP addresses within LANs and WANs to prov=
ide
additional address space
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
18 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
IP Addressing (continued)
&#=
8226; Private
IP addresses
– Series of IP numbers not permitted on packets <=
/span>that
travel on the Internet
&#=
8226; Network
Address Translation (NAT) device
&#=
8211; Used
in subnetting to convert private IP addresses into normal IP
addresses
&#=
8226; Internet
Protocol version 6 (IPv6)
&=
#8211; Protocol
that will replace IPv4
&=
#8211; Uses
a 128-bit number for addresses
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
19 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
Domain Names
• A domain
name is a set of words assigned to a specific IP address
=
• Top-level
domain (or TLD)
– Rightmost
part of a domain name
• Internet
Corporation for Assigned Names and Numbers (ICANN)
– Responsi=
ble
for managing domain names and coordinating them with IP
address registrars
Chapter 2: Technology Infrastructure: The Internet and the World Wide
Web
Electronic
Commerce, Seventh Annual Edition
20 <=
span
style=3D'font-size:111%;mso-special-format:lastCR;display:none'>
![](3D"slide0008_image002.jpg")
=
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=