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1. Advanced Diploma of Information Technology
MIT Nguyễn Hữu Phát
Kent International College
80 hours
2.
3. 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
E-Commerce: The Second Wave, Fifth Annual Edition 3
4. 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
E-Commerce: The Second Wave, Fifth Annual Edition 4
5. 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
E-Commerce: The Second Wave, Fifth Annual Edition 5
6. 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
E-Commerce: The Second Wave, Fifth Annual Edition 6
7. 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
E-Commerce: The Second Wave, Fifth Annual Edition 7
8. 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
E-Commerce: The Second Wave, Fifth Annual Edition 8
11. The $23.4 billion in annual internet advertising spending exceeded advertising on cable
TV for the first time (which was $21.4 billion), and took the No. 3 spot behind national
and local TV ads ($29.8 billion) and newspaper ads ($34.4 billion).
12. Internet advertising is almost twice as large as broadcast TV advertising was in its 14th
year ($13.3 billion) and nearly four times as large as cable TV ($6.5 billion).
13. 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
14. 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
15. 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
16. 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
17. 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
19. 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
20. 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
E-Commerce: The Second Wave, Fifth Annual Edition 20
21. Internet Protocol version 4/6 (IPv4/6)
› Uses a 32-bit number to identify
computers connected to the Internet
Base 2 (binary) number system
› Used by computers to perform internal
calculations
Subnetting
› Use of reserved private IP addresses within
LANs and WANs to provide additional
address space
E-Commerce: The Second Wave, Fifth Annual Edition 21
22. 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
23. 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
25. 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
26. 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)
27. 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
28. 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)
29. 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
30.
31.
32.
33.
34. 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
35. 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
E-Commerce: The Second Wave, Fifth Annual Edition 35
36. 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
E-Commerce: The Second Wave, Fifth Annual Edition 36
37. 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
E-Commerce: The Second Wave, Fifth Annual Edition 37
39. 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
40. 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
41. 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
42. 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
43. 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
44. 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
E-Commerce: The Second Wave, Fifth Annual Edition 44
45. 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
46. 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
47. 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
E-Commerce: The Second Wave, Fifth Annual Edition 47
48. 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
E-Commerce: The Second Wave, Fifth Annual Edition 48
49. 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
50. 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
51. 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
E-Commerce: The Second Wave, Fifth Annual Edition 51
52. 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
53. 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)
E-Commerce: The Second Wave, Fifth Annual Edition 53
54. 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 54