CHAPTER 4
Networks
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Chapter 4:
Networks
4.1 What Is a Computer Network?
4.2 Network Fundamentals
4.3 The Internet and the World Wide Web
4.4 Internet Network Applications
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LEARNING OBJECTIVES
1. Define the term “computer network”, and compare and
contrast the two major types of networks.
2. Describe the differences among the three types of
wireline communications media, and discuss the main
advantages and disadvantages of each type.
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LEARNING OBJECTIVES
(CONTINUED)
3. Differentiate between the Internet and the World Wide
Web, and identify the most common methods for
accessing the Internet.
4. Identify six major categories of network applications,
provide an example of each, and explain how that
application supports business functions.
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OPENING CASE
4.1 THE NETWORK NEUTRALITY WARS
The Problem
The CEO of Netflix was asked whether the Internet’s
infrastructure can withstand the strain of his expanding
business, which had more than 36 million subscribers
worldwide as of mid-2013. He replied: “If there’s
anything you’d want to bet on, it’s that technology will
make bandwidth faster and cheaper.” That bet may not
be as safe as it seems and the explosion of streaming
video and mobile technologies in recent years is
beginning to cause problems. The Internet was built to
transmit content such as e-mails and web pages. In
contrast, media items such as high-definition movies are
magnitudes greater in size
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THE NETWORK NEUTRALITY
WARS
Solution
– One possible solution is net neutrality. Network neutrality is the
concept that ISPs must allow customers equal access to content
and applications, regardless of the source or nature of the
content.
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THE NETWORK NEUTRALITY
WARS
The Results
– Most analysts expect that the heaviest data consumers
eventually will have to pay more, most likely in the form of tiered
pricing plans. North Americans, however, have never
experienced limits on the amount of data they upload and
download. Nevertheless, wireless networks have already moved
in the direction of these plans.
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THE NETWORK NEUTRALITY
WARS
•
Discussion
– Why are telecommunications and cable companies are not in
favour of net neutrality?
– Why are ISP’s in favour of net neutrality?
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4.1 WHAT IS A COMPUTER
NETWORK?
•
Fundamental points about network computing:
– They constantly exchange data with one another.
– The exchange of data provide companies with a number of very
significant advantages.
– This exchange can take place over any distance & over
networks of any size.
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WHAT IS A COMPUTER NETWORK
(CONTINUED)
•
•
Bandwidth is the transmission capacity of a network; it
is stated in bits per second.
Broadband refers to network transmission capacities
ranging from approximately 1 million bits per second
(megabits/s) to as much as 20 megabits/s with fibre-tothe-home.
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SIZE OF COMPUTER NETWORKS
• There are various types of computer networks, ranging
from small to worldwide. They include (from smallest to
largest):
–
–
–
–
personal area networks (PANs)
local area networks (LANs)
metropolitan area networks (MANs)
wide area networks (WANs) and the Internet
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LOCAL AREA NETWORKS
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WIDE AREA NETWORKS
•
•
•
•
Wide area networks (WANs) are networks that cover
large geographic areas.
WANs typically connect multiple LANs.
WANs have large capacity, and they typically combine
multiple channels (for example, fibre-optic cables,
microwave, and satellite).
WANs also contain routers. A router is a
communications processor that routes messages from a
LAN to the Internet, across several connected LANs, or
across a wide area network such as the Internet.
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ENTERPRISE NETWORK
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4.2 NETWORK FUNDAMENTALS
•
•
•
•
•
Analog and Digital Signals
Communications Media and Channels
Twisted-Pair Wire
Coaxial Cable
Fibre-Optic Cables
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ANALOG AND DIGITAL SIGNALS
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MODEMS
•
There are three types of modems:
– dial-up modems
– cable modems
– DSL modems
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COMMUNICATIONS MEDIA
AND CHANNELS
1. Twisted-pair wire
2. Coaxial cable
3. Fibre optics
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TRANSMISSION TECHNOLOGIES
•
•
•
•
•
•
•
Digital subscriber line (DSL)
Asynchronous transfer mode (ATM)
Synchronous optical network (SONET)
T-carrier system
Network Protocols
Ethernet
Transmission Control Protocol/Internet Protocol
(TCP/IP)
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THE FOUR LAYERS OF THE
TCP/IP PROTOCOL
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PACKET SWITCHING
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TYPES OF NETWORK
PROCESSING
•
•
Client/server computing
Peer-to-peer processing
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4.3 THE INTERNET AND THE
WORLD WIDE WEB
•
•
•
Accessing the Internet
Connecting via an On-line Service (ISP)
Connecting via Other Means (smart phones, ipads)
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ACCESSING THE INTERNET
•
•
Each computer on the
Internet has an assigned
address, called the
Internet protocol (IP)
address.
IP addresses must be
unique
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ADDRESSES ON THE INTERNET
•
Domain names
– Top-level domain
– Name of the organization
– Name of the specific computer
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ADDRESSES ON THE INTERNET
IPv4
32 bits
IPv6
128 bits
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THE FUTURE OF THE INTERNET
•
Many experts are now concerned that Internet users will
experience brownouts (temporary unavailability or
slower speeds) due to three factors:
1.
2.
3.
the increasing number of people who work on-line,
the soaring popularity of websites such as YouTube that
require large amounts of bandwidth, and
the tremendous demand for high-definition television delivered
over the Internet.
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THE WORLD WIDE WEB
•
The World Wide Web
–
–
–
–
–
Not the same thing as the Internet
Home page
Website
Uniform resource locator
Browser
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BROWSER COMPETITION
•
•
•
•
Companies are investing increasing amounts of resources in their
browsers (Safari, Google Chrome, Mozilla Firefox, Opera ,
Microsoft Internet Explorer).
A couple of developments are behind this trend. The first is Google,
whose big plans for its Chrome browser forced Microsoft to pay
more attention to its own browser, Internet Explorer (IE).
The second factor was a decision by the European Union (EU).
Starting in March 2010, the EU required computer manufacturers to
offer European customers more freedom to choose their software.
Regardless of which browser users select they should take into
consideration issues of security and privacy.
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4.4 INTERNET NETWORK
APPLICATIONS
•
•
•
•
•
•
Discovery
Communication
Collaboration
E-Learning and Distance Learning
Virtual Universities
Telecommuting
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DISCOVERY
1. Search engines
2. Metasearch engines http://www.kartoo.com/
3. Publication of material in foreign languages
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PORTALS
•
•
•
•
•
Commercial (public) portals
Affinity portals
Mobile portals
Corporate portals
Industry wide portals
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AFFINITY PORTAL (EXAMPLE)
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COMMUNICATION
•
•
•
•
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Electronic mail (e-mail)
Web-based call centers (customer call center)
Electronic chat room
Voice
Unified
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VOICE COMMUNICATION
•
Two examples of Internet telephony (VoIP)
– Skype
– Vongae
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COLLABORATION
•
•
•
Work group
Work Flow
Virtual group (team)
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COLLABORATION (CONTINUED)
•
•
•
•
Virtual collaboration
Collaboration software
Electronic Teleconferencing
E-Learning and Distance Learning
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CROWDSOURCING
•
Crowdsourcing refers to outsourcing a task to an
undefined, generally large group of people in the form of
an open call.
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SOFTWARE PRODUCTS
SUPPORTING COLLABORATION
•
•
•
•
Google Docs (http://docs.google.com) is a free, web-based
word processor, spreadsheet, and presentation application.
Microsoft’s SharePoint product
(www.microsoft.com/Sharepoint/default.mspx) provides
shared content with version control.
IBM’s Lotus Quickr (www.ibm.com/lotus/quickr) product
provides shared content with version control in the form of
document directories with check-in and check-out features
based on user privileges.
Jive’s (www.jivesoftware.com) uses web collaboration and
communication tools such as forums, wikis, and blogs to
allow people to share content with version management, via
discussion rooms, calendars, and to-do lists.
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ELECTRONIC
TELECONFERENCING
•
•
The latest version of teleconferencing, telepresence
systems, enable participants to seamlessly share data,
voice, images, graphics, video, and animation
electronically.
See video on Cisco Magic
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E-LEARNING AND DISTANCE
LEARNING
•
•
E-Learning refers to learning supported by the Web.
Distance learning (DL) refers to any learning situation
in which teachers and students do not meet face-toface.
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BENEFITS OF E-LEARNING
•
•
•
•
Online materials deliver high-quality, current content.
Students have the flexibility of learning from any place
at any time at their own pace.
Learning time generally is shorter, and more people can
be trained due to faster training time.
Training costs can be reduced.
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DRAWBACKS OF E-LEARNING
•
•
•
The purchase of additional multimedia equipment may
be necessary.
Students must be computer literate and may miss the
face-to-face interaction with instructors.
There are issues with assessing students’ work, as
instructors really do not know who completed
assignments.
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VIRTUAL UNIVERSITIES
•
Virtual universities are on-line universities in which
students take classes from home or at an off-site
location, via the Internet. A large number of existing
universities offer on-line education of some form. Other
universities offer limited on-line courses and degrees
but use innovative teaching methods and multimedia
support in the traditional classroom.
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TELECOMMUTING
•
Knowledge workers are being called the distributed
workforce, or digital nomads. This group of highly prized
workers is now able to work anywhere and anytime, a
process called telecommuting.
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TELECOMMUTING BENEFITS
•
For Employees
– Reduced stress, improved family life
– Employment opportunities for single parents and persons with
disabilities
•
For Employers
– Increased productivity
– Ability to retain skilled employees
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TELECOMMUTING
DISADVANTAGES
•
For Employees
–
–
–
–
–
•
Feelings of isolation
Possible loss of fringe benefits
Lack of socialization
Lower pay (in some cases)
Potential for slower promotions
For Employers
– Difficulties in supervising work
– Potential information security problems
– Additional training costs
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CHAPTER CLOSING
•
•
•
•
•
A computer network is a system that connects computers via
communications media so that data and information can be
transmitted among them.
There are three types of wireline communications media:
twisted-pair, coaxial and fibre-optic cables
The Internet is a global network of computer networks, using
a common communications protocol, TCP/IP.
The World Wide Web is a system that stores, retrieves,
formats, and displays information accessible through a
browser.
There are six major categories of network applications:
Discovery, Networks, E-learning, Collaboration, Virtual
universities and Telecommuting
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Copyright
Copyright © 2014 John Wiley & Sons Canada, Ltd. All rights
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assume no responsibility for errors, omissions, or damages
caused by the use of these files or programs or from the use
of the information contained herein.
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