The document discusses the history and technical aspects of the Internet and World Wide Web. It covers the origins of the ARPANET network in the 1960s, the development of protocols like TCP/IP and HTML, and different connection methods including DSL, cable, and wireless. It also examines intranets, extranets, Internet2, and the goals of the Semantic Web to add meaning to words on webpages through XML tagging.

2. Objectives
In this chapter, you will learn about:
The origin, growth, and current structure of the
Internet
How packet-switched networks are combined to
form the Internet
How Internet protocols and Internet addressing
work
The history and use of markup languages on the
Web, including SGML, HTML, and XML
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3. Objectives
How HTML tags and links work on the World Wide
Web
The differences among internets, intranets, and
extranets
Options for connecting to the Internet, including cost
and bandwidth factors
About Internet2 and the Semantic Web
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4. The Internet and the World Wide Web
Computer network
Any technology that allows people to connect
computers to each other
The Internet
A large system of interconnected computer networks
spanning the globe
World Wide Web
A subset of computers on the Internet
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5. Origins of the Internet
Early 1960s
U.S. Department of Defense funded research to
explore creating a worldwide network
In1969, Defense Department researchers
Connected four computers into network called
ARPANET
Throughout 1970s and 1980s
Academic researchers connected to ARPANET and
contributed to its technological developments
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6. New Uses for the Internet
1972
E-mail was born
Mailing list
E-mail address that forwards any message received
to any user who has subscribed to the list
 Usenet
Started by group of students and programmers at
Duke University and the University of North
Carolina
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7. Growth of the Internet
In 1991, NSF
Eased restrictions on commercial Internet activity
Began implementing plans to privatize the Internet
Network access points (NAPs)
Basis of new structure Internet
Network access providers
Sell Internet access rights directly to larger
customers and indirectly to smaller firms and
individuals through ISPs
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8. Growth of the Internet
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9. Emergence of the World Wide Web
The Web
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
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10. Emergence of the World Wide
Web (Continued)
Tim Berners-Lee
Developed code for hypertext server program
Hypertext server
Stores files written in hypertext markup language
Lets other computers connect to it and read files
Hypertext Markup Language (HTML)
Includes set of codes (or tags) attached to text
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11. Packet-Switched Networks
Local area network (LAN)
Network of computers located close together
Wide area networks (WANs)
Networks of computers connected over greater
distances
Circuit
Combination of telephone lines and closed switches
that connect them to each other
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12. Packet-Switched Networks
(Continued)
Circuit switching
Centrally controlled, single-connection model
Packets
Files and e-mail messages on a packet-switched network
that are broken down into small pieces
Travel from computer to computer along the
interconnected networks until they reach their
destinations
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13. 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 path on which to send packet
Programs apply their routing algorithms to information
they have stored in routing tables
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14. Router-based Architecture of the Internet
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15. Internet Protocols
Protocol
Collection of rules for formatting, ordering, and error-
checking data sent across a network
Rules contributing to success of Internet
Independent 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 their source network
Router computers act as receive-and-forward devices
No global control exists over the network
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16. TCP/IP
TCP
Controls disassembly of a message or a file into packets
before transmission over Internet
Controls reassembly of packets into their original
formats when they reach their destinations
IP
Specifies addressing details for each packet
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17. IP Addressing
Internet Protocol version 4 (IPv4)
Uses a 32-bit number to identify computers
connected to the Internet
Base 2 (binary) number system
Used by computers to perform internal calculations
Sub netting
Use of reserved private IP addresses within LANs
and WANs to provide additional address space
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18. IP Addressing (Continued)
Private IP addresses
Series of IP numbers not permitted on packets that
travel on the Internet
Network Address Translation (NAT) device
Used in subnetting to convert private IP addresses into
normal IP addresses
Internet Protocol version 6 (IPv6)
Protocol that will replace IPv4
Uses a 128-bit number for addresses
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19. Domain Names
Sets of words assigned to specific IP addresses
Top-level domain (or TLD)
Rightmost part of a domain name
Internet Corporation for Assigned Names and
Numbers (ICANN)
Responsible for managing domain names and
coordinating them with IP address registrars
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20. Top-level Domain Names
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21. Web Page Request and Delivery Protocols
Web client computers
Run software called Web client software or Web
browser software
Web server computer
Runs software called Web server software
Client/server architecture
Combination of client computers running Web
client software and server computers running Web
server software
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22. Web Page Request and Delivery
Protocols (Continued)
Hypertext Transfer Protocol (HTTP)
Set of rules for delivering Web page files over the
Internet
Uniform Resource Locator (URL)
Combination of the protocol name and domain
name
Allows user to locate a resource (the Web page) on
another computer (the Web server)
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23. Electronic Mail Protocols
Electronic mail (e-mail)
Must also be formatted according to common set of
rules
 E-mail server
Computer devoted to handling e-mail
E-mail client software
Used to read and send e-mail
Example: Microsoft Outlook, Netscape Messenger
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24. Electronic Mail Protocols (Continued)
Simple Mail Transfer Protocol (SMTP)
Specifies format of a mail message
 Post Office Protocol (POP)
POP message can tell the e-mail server to
 Send mail to user’s computer and delete it from e-mail
server
 Send mail to user’s computer and not delete it
 Simply ask whether new mail has arrived
Provides support for Multipurpose Internet Mail
Extensions (MIME)
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25. Markup Languages and the Web
Text markup language
Specifies set of tags that are inserted into text
Standard Generalized Markup Language (SGML)
Older and complex text markup language
A meta language
World Wide Web Consortium (W3C)
Not-for-profit group that maintains standards for the
Web
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26. Development of Markup Languages
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27. Standard Generalized Markup Language
Offers a system of marking up documents that is
independent of any software application
Nonproprietary and platform independent
Offers user-defined tags
Costly to set up and maintain
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28. Hypertext Markup Language (HTML)
Prevalent markup language used to create documents
on the Web today
HTML tags
Interpreted by Web browser and used by it to format
the display of the text
HTML Links
Linear hyperlink structure
Hierarchical hyperlink structure
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29. Hypertext Markup Language
(HTML) (Continued)
Scripting languages and style sheets
Most common scripting languages
 JavaScript, JScript, Perl, and VBScript
Cascading Style Sheets (CSS)
 Sets of instructions that give Web developers more
control over the format of displayed pages
 Style sheet
 Usually stored in a separate file
 Referenced using the HTML style tag
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30. Extensible Markup Language (XML)
Uses paired start and stop tags
Includes data management capabilities that HTML
cannot provide
Differences between XML and HTML
XML is not a markup language with defined tags
XML tags do not specify how text appears on a Web
page
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31. Processing a Request for an XML Page
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32. Intranets and Extranets
Intranet
Interconnected network that does not extend beyond
organization that created it
Extranet
Intranet extended to include entities outside
boundaries of organization
Connects companies with suppliers, business partners,
or other authorized users
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33. Public and Private Networks
Public network
Any computer network or telecommunications
network available to the public
Private network
A private, leased-line connection between two
companies that physically connects their intranets
Leased line
A permanent telephone connection between two
points
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34. Virtual Private Network (VPN)
Extranet that uses public networks and their
protocols
IP tunneling
Effectively creates a private passageway through the
public Internet
Encapsulation
Process used by VPN software
VPN software
Must be installed on the computers at both ends of the
transmission
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35. Internet Connection Options
Bandwidth
Amount of data that can travel through a
communication line per unit of time
Net bandwidth
Actual speed that information travels
Symmetric connections
Provide same bandwidth in both directions
Asymmetric connections
Provide different bandwidths for each direction
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36. Voice-Grade Telephone
Connections
POTS, or plain old telephone service
Uses existing telephone lines and analog modem
Provide bandwidth between 28 and 56 Kbps
Digital Subscriber Line (DSL)
Connection methods do not use modem
Integrated Services Digital Network (ISDN)
Offers bandwidths between 128 Kbps and 256 Kbps
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37. Broadband Connections
Operate at speeds of greater than 200 Kbps
Asymmetric digital subscriber (ADSL)
Transmission bandwidth is from 100 to 640 Kbps
upstream and from 1.5 to 9 Mbps downstream
Cable modems
Provide transmission speeds between 300 Kbps and 1
Mbps
DSL
Private line with no competing traffic
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38. Leased-Line Connections
DS0 (digital signal zero)
Telephone line designed to carry 1 digital signal
T1 line (also called a DS1)
Carries 24 DS0 lines and operates at 1.544 Mbps
Fractional T1
Provides service speeds of 128 Kbps and upward in 128-
Kbps increments
T3 service (also called DS3)
Offers 44.736 Mbps
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39. Wireless Connections
Bluetooth
Designed for personal use over short distances
Low-bandwidth technology, with speeds of up to
722 Kbps
Networks are called personal area networks (PANs)
or piconets
Consumes very little power
Devices can discover each other and exchange
information automatically
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40. Wireless Ethernet (Wi-Fi or 802.11b)
Most common wireless connection technology for use
on LANs
Wireless access point (WAP)
Device that transmits network packets between Wi-Fi-
equipped computers and other devices
Has potential bandwidth of 11 Mbps and range of
about 300 feet
Devices are capable of roaming
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41. Wireless Ethernet (Wi-Fi or 802.11b)
(Continued)
802.11a protocol
Capable of transmitting data at speeds up to 54
Mbps
802.11g protocol
Has 54 Mbps speed of 802.11a
Compatible with 802.11b devices
802.11n
Expected to offer speeds up to 320 Mbps
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42. Fixed-Point Wireless
One version uses system of repeaters to forward radio
signal from ISP to customers
Repeaters
Transmitter-receiver devices (transceivers)
Mesh Routing
Directly transmits Wi-Fi packets through hundreds, or
even thousands, of short-range transceivers
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43. Cellular Telephone Networks
Third-generation (3G) cell phones
Combine latest technologies available today
Short message service (SMS)
Protocol used to send and receive short text messages
Mobile commerce (m-commerce)
Describes the kinds of resources people might want to
access using wireless devices
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44. Internet2 and the Semantic Web
Internet2
Experimental test bed for new networking technologies
Has achieved bandwidths of 10 Gbps and more on parts
of its network
Used by universities to conduct large collaborative
research projects
44

45. Internet2 and the Semantic Web
(Continued)
Semantic Web
Project by Tim Berners-Lee
 If successful
 Would result in words on Web pages being tagged (using
XML) with their meanings
Resource description framework (RDF)
Set of standards for XML syntax
Ontology
Set of standards that defines relationships among
RDF standards and specific XML tags
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46. Summary
TCP/IP
Protocol suite used to create and transport information
packets across the Internet
POP, SMTP, and IMAP
Protocols that help manage e-mail
Languages derived from SGML
Hypertext Markup Language (HTML)
Extensible Markup Language (XML)
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47. Summary
Intranets
Private internal networks
Extranet
Used when companies want to collaborate with
suppliers, partners, or customers
Internet2
Experimental network built by a consortium of research
universities and businesses
E-Commerce: The Second Wave, Fifth Annual Edition 47