Fundamentals of Information
Systems
Fourth Edition
Chapter 4
Telecommunications, the Internet,
Intranets, and Extranets
Principles and Learning Objectives
• The effective use of communications technology is
essential to organizational success by enabling
more people to send and receive all forms of
information over greater distances at faster and
faster rates
– Define the term telecommunications and describe
the components of a telecommunications system
including media and hardware devices
– Identify several network types and the uses and
limitations of each
– Define the term communications protocol and
identify several common ones
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Principles and Learning Objectives
(continued)
• The Internet and the Web provide a wide range of
services, some of which are effective and practical
for use today, others that are still evolving, and still
others that will fade away from lack of use
– Briefly describe how the Internet works, including
alternatives for connecting to it and the role of
Internet service providers
– Describe how the World Wide Web works and the
use of Web browsers, search engines, and other
Web tools
– Identify programming languages and tools used to
create Web content
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Principles and Learning Objectives
(continued)
• Because the Internet and the World Wide Web are
becoming more universally used and accepted for
business use, management, service and speed,
privacy, and security issues must continually be
addressed and resolved
– Identify and briefly describe several applications
associated with the Internet and the Web
– Define the terms intranet and extranet and discuss
how organizations are using them
– Identify several issues associated with the use of
networks
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Why Learn About Telecommunications, the
Internet, Intranets and Extranets?
• Need to access data wherever it resides
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Fast, reliable communications
Exchange messages
Upload/download data and software
Route business transactions
Connect to remote databases
Send output to printers
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Why Learn About Telecommunications
and Networks?
• Need to access data wherever it resides
–
–
–
–
–
–
Fast, reliable communications
Exchange messages
Upload/download data and software
Route business transactions
Connect to remote databases
Send output to printers
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An Overview of Telecommunications
• Telecommunications: the electronic transmission
of signals for communications
• Telecommunications medium: anything that
carries an electronic signal and interfaces between
a sending device and a receiving device
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An Overview of Telecommunications
(continued)
Figure 4.1: Elements of a Telecommunications System
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Channel Bandwidth
• Telecommunications professionals consider the
capacity of the communications path or channel
when they recommend transmission media for a
business
• Channel bandwidth: the rate at which data is
exchanged over a communication channel
– Usually measured in bits per second (bps)
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Communications Media
Table 4.1: Guided Transmission Media Types
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Communications Media (continued)
Table 4.2: Wireless Technologies
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Telecommunications Hardware
Table 4.3: Common Telecommunications Devices
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Services
• Digital subscriber line (DSL):
telecommunications service that delivers highspeed Internet access to homes and small
businesses over the existing phone lines of the
local telephone network
• All major long distance carriers offer wireless
telecommunications services that enable you to
place phone calls or access the Internet
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Networks and Distributed Processing
• Computer network: the communications media,
devices, and software needed to connect two or
more computer systems and/or devices
• Network nodes: the computers and devices on the
networks
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Network Types
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•
•
•
•
•
Personal area network (PAN)
Local area network (LAN)
Metropolitan area network (MAN)
Wide area network (WAN)
International networks
Mesh networking
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Network Types (continued)
Figure 4.4: A Typical LAN
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Network Types (continued)
Figure 4.5: A Wide Area Network
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Distributed Processing
• Centralized processing: all processing occurs in a
single location or facility
• Decentralized processing: processing devices
are placed at various remote locations
• Distributed processing: computers are placed at
remote locations but connected to each other via a
network
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Client/Server Systems
• Client/Server system: multiple computer platforms
are dedicated to special functions, such as
database management, printing, communications,
and program execution
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Client/Server Systems (continued)
Figure 4.8: Client/Server Connection
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Communications Software and
Protocols
• Communications protocol: a set of rules that
govern the exchange of information over a
communications channel
• Protocols govern several levels of a
telecommunications network, such as:
– Hardware device level
– Application program level
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Communications Software and
Protocols (continued)
Table 4.4: Common Telecommunications Protocols
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Wireless Communications Protocols
• Wireless communications protocols are still
evolving as the industry matures
• The Institute for Electrical and Electronic Engineers
(IEEE) has been instrumental in defining numerous
telecommunications standards
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Wireless Communications Protocols
(continued)
Table 4.5: Wireless Networks Based on IEEE 802.xx Standards
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Communications Software
• Network operating system (NOS): systems
software that controls the computer systems and
devices on a network and allows them to
communicate with each other
• Network-management software: software that a
manager uses on a networked desktop
– Monitors the use of individual computers and shared
hardware (such as printers)
– Scans for viruses
– Ensures compliance with software licenses
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Use and Functioning of the Internet
• Internet: a collection of interconnected networks,
all freely exchanging information
• ARPANET
– The ancestor of the Internet
– A project started by the U.S. Department of Defense
(DoD) in 1969
• Internet Protocol (IP): communication standard
that enables traffic to be routed from one network
to another as needed
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How the Internet Works
• The Internet transmits data from one computer
(called a host) to another
• If the receiving computer is on a network to which
the first computer is directly connected, it can send
the message directly
• If the receiving computer is not on a network to
which the sending computer is connected, the
sending computer relays the message to another
computer that can forward it
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How the Internet Works (continued)
• Data is passed in chunks called packets
• Transmission Control Protocol (TCP): widely
used transport-layer protocol that is used in
combination with IP by most Internet applications
• Uniform Resource Locator (URL): an assigned
address on the Internet for each computer
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How the Internet Works (continued)
• Accessing the Internet
– Connect via LAN server
– Connect via Serial Line Internet Protocol
(SLIP)/Point-to-Point Protocol (PPP)
– Connect via an online service
– Several other ways to connect
• Example: WAP
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How the Internet Works (continued)
Figure 4.11: Routing Messages over the Internet
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How the Internet Works (continued)
Figure 4.12: Several Ways to Access the Internet
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Internet Service Providers
• Internet service provider (ISP): any company that
provides individuals or organizations with access to
the Internet
• Most charge a monthly fee
• Many ISPs and online services offer broadband
Internet access through digital subscriber lines
(DSLs), cable, or satellite transmission
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Internet Service Providers (continued)
Table 4.7: A Representative List of Internet Service Providers
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The World Wide Web
• The Web, WWW, or W3
• A menu-based system that uses the client/server
model
• Organizes Internet resources throughout the world
into a series of menu pages, or screens, that
appear on your computer
• Hypermedia: tools that connect the data on Web
pages, allowing users to access topics in whatever
order they want
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The World Wide Web (continued)
• Hypertext Markup Language (HTML): the
standard page description language for Web pages
• HTML tags: codes that let the Web browser know
how to format text - as a heading, as a list, or as
body text - and whether images, sound, and other
elements should be inserted
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The World Wide Web (continued)
Figure 4.13: Sample Hypertext Markup Language
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Web Browsers
• Web browser: software that creates a unique,
hypermedia-based menu on a computer screen,
providing a graphical interface to the Web
• The menu consists of graphics, titles, and text with
hypertext links
• Popular Web browsers: Microsoft Internet Explorer,
Netscape Navigator, Mozilla Firefox, Apple
Computer’s Safari
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Search Engines and Web Research
• Search engine: Web search tool
– Examples: Yahoo.com, Google.com
• Most search engines are free
• Searches can use words, such as AND and OR to
refine the search
• Meta-search engine: submits keywords to several
individual search engines and returns results from
all these search engines
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Search Engines and Web Research
(continued)
Table 4.10 Popular Search Engines
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Web Programming Languages
• Java
– An object-oriented programming language from Sun
Microsystems based on C++
– Allows small programs (applets) to be embedded
within an HTML document
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Developing Web Content
• Products that greatly simplify the creation of a Web
page
– Example: .NET platform
• Other Web publishing packages include Bubbler,
Homestead QuickSites, and JobSpot
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Web Services
• Standards and tools that streamline and simplify
communication among Web sites for business and
personal purposes
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Internet and Web Applications: E-Mail,
Instant Messaging, and Push
Technology
• E-mail is no longer limited to simple text messages
– Sound and images can be embedded in messages
– Files that contain text documents, spreadsheets,
graphs, or executable programs can be attached
• Instant messaging: allows two or more individuals
to communicate online using the Internet
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Internet Cell Phones and Handheld
Computers
• Some cell phones can be connected to the Internet
to:
– Search for information
– Buy products
– Chat with business associates and friends
• Handheld computers and other devices can be
connected to the Internet using phone lines or
wireless connections, such as Wi-Fi
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Career Information and Job Searching
• Internet is an excellent source of job-related
information
• Most medium and large companies have Internet
sites that list open positions, salaries, benefits, and
people to contact for further information
• Some sites can help you develop a good résumé
and an effective cover letter, apply for jobs online,
prepare for a job interview, and negotiate a good
employment contract
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Web Log (Blog), Video Log (Vlog), and
Podcasting
• Web log (blog): Web site that people can create
and use to write about their observations,
experiences, and feelings on a wide range of topics
• Video log (vlog): video content placed on the
Internet using the same overall approach as a blog
• Podcast: audio blog, like a personal radio station
on the Internet
– Extends blogging by adding audio messages
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Chat Rooms
• Chat room: facility that enables two or more
people to engage in interactive “conversations”
over the Internet
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Internet Phone and Videoconferencing
Services
• Internet phone service enables you to
communicate with others around the world
– Relatively inexpensive
– Useful for international calls
– Ability to keep your phone number when you move
to another location
• Internet videoconferencing
– Supports both voice and visual communications
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Content Streaming
• Content streaming: a method for transferring
multimedia files over the Internet so that the data
stream of voice and pictures plays more or less
continuously without a break, or with very few
breaks
– Enables users to browse large files in real time
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Shopping on the Web
• Shopping on the Web for books, clothes, cars,
medications, and even medical advice can be
convenient, easy, and cost effective
• Bot: software tool that searches the Web for
information, products, or prices
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Web Auctions
• Web auction: Internet site that matches buyers
and sellers
– eBay is one of the most popular auction sites
• Traditional companies are starting their own
auction sites
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Music, Radio, Video, and TV on the
Internet
• Music, radio, and video are hot growth areas on the
Internet
• Audio and video programs can be played on the
Internet, or files can be downloaded for later use
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Office on the Web
• Many services and software products give you
remote access to your files and programs over the
Internet
– Examples: Avvenu, EasyReach, BeInSync
• Companies that offer remote access include
MyWebEx PC Pro, Citrix Online, and Laplink
• Works best with broadband Internet access
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Other Internet Services and
Applications
• Internet services are constantly emerging
– Libraries
– Critical information during times of disaster or
terrorism
– Critical medical information
– Translation
– Distance learning
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Intranets and Extranets
• Intranet
– Internal corporate network built using Internet and
World Wide Web standards and products
– Used by employees to gain access to corporate
information
– Reduces need for paper
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Intranets and Extranets (continued)
• Extranet
– A network based on Web technologies that links
selected resources of a company’s intranet with its
customers, suppliers, or other business partners
• Virtual private network (VPN): secure connection
between two points across the Internet
• Tunneling: process by which VPNs transfer
information by encapsulating traffic in IP packets
over the Internet
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Net Issues
• Management issues
– No centralized governing body controls the
Internet
• Service and speed issues
– Web server computers can be overwhelmed by
the amount of “hits” (requests for pages)
• Privacy, fraud, security, and unauthorized
Internet sites
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Summary
• Telecommunications: electronic transmission of
signals for communications
• Computer network: communications media,
devices, and software needed to connect two or
more computer systems or devices
• Network types: personal area network (PAN), local
area network (LAN), metropolitan area network
(MAN), wide area network (WAN), and international
networks
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Summary (continued)
• Internet: collection of interconnected networks, all
freely exchanging information
• Internet Protocol (IP): communication standard that
enables traffic to be routed from one network to
another as needed
• Uniform Resource Locator (URL): an assigned
address on the Internet for each computer
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Summary (continued)
• Intranet: internal corporate network built using
Internet and World Wide Web standards and
protocols
• Extranet: network based on Web technologies that
links selected resources of a company’s intranet
with its customers, suppliers, or other business
partners
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