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Digital Planet:
Tomorrow’s Technology
and You
George Beekman • Ben Beekman
Tenth Edition
Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Digital Planet:
Tomorrow’s Technology and You
Chapter 8
Networking and Digital
Communication
Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Chapter 8 Objectives
 Describe the basic types of technology that make
telecommunication possible
 Describe the nature and function of local area
networks and wide area networks
 Discuss the uses and implications of several different
forms of online communication and collaboration
 Explain how wireless network technology is
transforming the ways people work and
communicate
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Chapter 8 Objectives (cont.)
Describe how wireless phone networks are
converging with digital data networks and the impact
of that convergence
Describe several ways to maximize effectiveness and
minimize risks of online communication
Describe how online social networks, wikis, and other
new tools for creating online communities compare
to traditional forms of community building
Describe current and future trends in
telecommunications and networking
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Arthur C. Clarke’s Magical Prophecy
• Arthur C. Clarke:
predicted the use of
geostationary
communications
satellites
• Considered to be the
father of satellite
communications
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Basic Network Anatomy
 A computer network is any system of two or
more computers that are linked together.
 Three essential components of every computer
system:
• Hardware
• Networks enable people to share computer hardware
resources
• Software
• Networks enable people to share data and software
programs.
• People
• Networks enable people to work together, communicate, and
play together
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Networks Near and Far
 LAN (local area network): computers are physically close
to each other – usually in same building
• Nodes: connected to hubs or switches, which allow any
node on the network to communicate with any other
 Ethernet: popular networking architecture developed in
the 1970s; now an industry standard
• Most networked computers today are connected to
networks today by ethernet cables, plugged into ethernet
plugs.
 Each node in a wireless network has a radio transmitter.
• Convenient for small networks in homes and small businesses
• Generally slower than wired LANs
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Networks Near and Far (cont.)
 WAN (wide area network): extends over a long distance
• Each networked LAN site is a node on the WAN
• Mostly used to link geographically dispersed corporate or
government offices
• Can use web of telephone lines, microwave relay towers,
and satellites that span the globe
 Routers: hardware devices or software programs that
route messages between networks
 Mesh networks: alternative to networks that uses
centralized routers
• Message hops from wireless device to wireless device
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The Importance of Bandwidth
 Bandwidth: refers to the amount of data that can be
transmitted through a communication medium in a
given amount of time
 Typically measured in kilobits or megabits per second
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The Importance of Bandwidth (cont.)
 Bandwidth can be affected by:
• Physical media of the network
• Amount of traffic on the network
• Type of network connection
 Fast Ethernet: carries traffic at 100 megabits per
second; provided all devices are fast Ethernet
compatible
 Gigabit Ethernet: standard is capable of transferring
1 gigabit of data per second
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Bandwidth (cont)
 Bandwidth is on the rise between LANs, due to fiber-optic
cables that are replacing copper wires in the worldwide
telephone network.
 Fiber optic cables use light waves to carry information at
lightening speeds
 A single fiber-optic cable can replace 10,000 copper
telephone cables.
• Used to connect most major communication hubs around the world.
 Many large businesses & government institutions are
connected to the global fiber-optic network
• Most homes and small businesses depend on copper wires for the
“last mile”.
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Communication Software
 Protocol: set of rules for the exchange of data
between devices
• Computers must follow the same protocols to understand
each other.
• Have code for messages like “Are you ready”., “I am about
to start sending a data file, and “Did you receive that file”
 TCP/IP: most famous protocol for computer
networking
• TCP/IP controls the exchange of data.
• Will be discussed in detail in next chapter
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Communication Software (cont.)
 Communication software takes many forms:
• NOS (network operating system): a system handles
communications among many workstations
• Examples: Novell’s Netware or Microsoft’s Windows Server
• Shields users from nuts-and-bolts level of detail
• Must be able to respond to requests from many computers.
• Client/server model: one or more computers act as
dedicated servers and all the remaining computers act as
clients
• Used by some LANs
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• Peer-to-peer model: every computer on the network is
both client and server
• Used by many small networks, including most
home networks
• Also called p-to-p or P2P
• Most desktop operating systems include all the
software needed to operate a peer-to-peer
network
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Linking In: Internet Connection
Technologies
 Early Day Connections
• Direct connection: a hardwired connection
• Faster than other connections
• Used by many businesses and schools
• Dial-up connection: uses modem and standard phone lines
• Modem stands for modulator/demodulator.
• Also called narrowband connections
 Broadband connection: greater bandwidth than
modems
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Linking In: Internet Connection
Technologies (cont.)
 Most common broadband alternatives:
• DSL (digital subscriber line): uses telephone lines that
carry voice calls
• Cable modems: use same network of coaxial cable as
television signals
• Satellite connections: use dishes that provide television
channels
• Wireless connections: used by growing numbers
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Wireless Network Technology
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Wi-Fi Technology
• Wireless access point (WAP):
central connection point for
wireless devices
• A Wi-Fi hot spot
• Wireless: Typically up to 120 feet
indoors and 300 feet outdoors.
• Use the 2.4 GHz and 5GHz band
of the radio spectrum
• Wide usage: Millions installed in
homes, schools, businesses,
coffee shops, airports,
restaurants, libraries, etc.
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Wi-Fi and WiMax Technology
• WiMAX (or 802.16): new long-distance radio-based
wireless standard in which a single tower can
provide access to a 25-square-mile area
• Line-of-sight connections up to 30 miles
• Can be used to connecting Wi-Fi networks
• Wi-Fi Area Security: If not secure, skilled snoopers
can “sniff” network traffic with laptop and read
what you are writing, collecting email addresses
and personal information
• WEP (wired equivalent privacy): encryption
scheme improves the security of wireless networks
• VPN (virtual private network): electronic "tunnel”
through the Internet that helps to prevent
eavesdropping
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Bluetooth Technology
 Bluetooth technology: named for Danish king who
overcame his country’s religious differences
• Overcomes differences between mobile phones, handheld
computers, and PCs, allowing communication between
different operating systems
• Range is limited to about 30 feet
• PAN (personal area network): links a variety of electronic
devices using Bluetooth technology
• Mobile phone to headset
• Wireless keyboard and mouse to keyboard
• Wireless game controller to the game console
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3G and 4G Technology
 3G and 4G technology: 3G networks carry
multimedia data and voice communications
simultaneously
• Used to support communications for mobile phones
• Lack true broadband speeds
• 4G networks have gigabit broadband speeds
• Larger mobile devices like the iPad compete with phones
for bandwidth on these networks
• Tethering: cabling a laptop to a mobile phone so it can
send and receive Internet data through the phone’s
wireless Internet connection
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Specialized Networks: From GPS to
Digital Money
• GPS (Global Positioning
System): specialized network
of the U.S. Department of
Defense
• GPS receiver uses signals
broadcast by satellites to
determine its position.
• At any point on planet, four
satellites will be above the
horizon.
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The Network Advantage
 Networks enable people to:
• Share computer hardware resources
• Print servers accept, prioritize, and process print jobs
• Share data and software programs
• Site licenses reduce costs for multiple copies of software
• Work, play, and communicate together
• Groupware enables several users to work on the same
document at the same time.
• E-commerce: Financial networks make credit card purchases,
automatic bill paying, electronic funds transfer, etc. possible
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A Home Computer Network
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The Many Faces of Email
 Email is built on protocols.
 SMTP (Simple Mail Transfer Protocol): sending mail
 POP (Post Office Protocol) or IMAP (Internet Message Access
Protocol): receiving mail
 Webmail: Web-based email, such as Gmail or Hotmail
 Attachments: formatted documents that are sent with an email
 Many email messages are in plain ASCII text – which require only
limited band-width.
 Often email software can handle HTML, which allows formatting
and inclusion of pictures.
 HTML use normally slow down email programs
 HTML allow email to carry web bugs
• Can notify sender of message opening, when received, and personal
information
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Email Issues
 Spam: unsolicited, junk email constitute the majority
of email.
• Some spam sneaks through even the best email filters
 Phishing: luring people into fake Web sites to
capture sensitive financial information
 Spreading Viruses: Mainly contained in attachments
and cost billions of dollars of damage
 Mailing lists: enable you to participate in email
discussion groups
• Moderated groups ensure quality of the discussions.
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Newsgroups, Web Forums, and Blogs
 Newsgroups: public discussion
on a particular subject
• Messages posted on virtual bulletin
board to read by anyone at anytime
 Web forums: accessed through a
Web browser
• Some require membership to post
• Newsgroups & forums may be
moderated to stop unproductive
message.
 Blogs: (weB LOG) frequently
updated online journals
• Political Blogs are an important
source of unmonitored information
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Instant Messaging, Text Messaging,
and Teleconferencing
 Asynchronous communication: poster and reader
don’t have to be logged in simultaneously
 IM (instant messaging): real-time communication
 Text messaging: uses SMS technology; more
limited than IM
 Chat room: public or private virtual conference
room
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Computer Telephony
• Voice mail: voice
messaging system
• Internet telephony: also
called Voice-over IP
• Many smart phones can
connect to the Internet.
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Online Survival Tips
• Let your system do as
much work as possible.
• Store names and
addresses in a computeraccessible address book.
• Don’t share emails and
passwords.
• Protect your privacy.
• Don’t open suspicious
attachments.
• Don’t get hooked by a
phishing expedition.
• Keep your security
systems up to date.
• Cross-check online
information sources.
• Beware of urban legends.
• Be aware and awake.
• Avoid information
overload.
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Social Networking, Role Playing, and
Virtual Communities
 Facebook, LinkedIn, Plaxo: social networking services
 Social networking sites: have privacy and safety
issues
 MMORPGs (massively multiplayer online roleplaying games): success requires cooperation among
groups of players
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Information Sharing: Social Bookmarking,
Wikis, Media Sharing, and Crowdsourcing
 Wiki: Web site designed to enable anyone who
accesses it to contribute to it
 YouTube is a cultural phenomenon for video sharing.
 Viral video: popular video that spreads as a virus
through email, blogs, or IMs
 Crowdsourcing: large community of people work on
a task
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Netiquette and Messaging Etiquette
• Say what you mean; say
it with care.
• Keep it short.
• Proofread your
messages.
• Don’t assume you are
anonymous.
• Learn the “nonverbal”
language of the Net.
• Know your
abbreviations.
• Keep your cool.
• Don’t be a source of
spam.
• Say no—and say
nothing—to spam.
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Sharing Resources: Peer-to-Peer, Grid,
and Cloud Computing
 Peer-to-peer: file sharing allows users to share files
by making their hard drives available to other users
rather than posting them on a central server
 Grid computing: sharing processing power rather
than sharing data
 Cloud computing: form of grid computing where the
resources come from the Internet rather than a
specific source
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Digital Communication in Perspective
 New technologies emerge all the time.
 Social networking is relatively new, but it has greatly
changed the way we communicate.
 Wikis and MMORPGs are at the heart of Web 2.0.
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Summary
 Networking is an important trend in computing today.
 LANs are made up of computers that are in close
proximity.
 Most networks use the Ethernet architecture.
 High-bandwidth connections can transmit large
amounts of information quickly.
 Wi-Fi makes it easy to connect devices to the Internet.
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Summary (cont.)
 Issues of privacy, security and censorship will
continue as the Internet grows.
 Email, instant messaging, and teleconferencing are
the most common forms of communication on
computer networks.
 Peer-to-peer computing was popularized by
music-sharing services.
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