CHAPTER 6
Networks
6.1 What Is a Computer Network?
A computer network is a system that connects computers and
other devices via communications
media so that data and information can be transmitted among them.
In a computer network, connected computers:
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Work together
Are interdependent
Exchange data with each
other
Local Area Networks
6.2 Network Fundamentals
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Analog and Digital Signals
Communications Media and Channels
Network Protocols
Types of Network Processing
Analog and Digital Signals
Communications Media and Channels
Twisted-pair wire
Coaxial cable
Fiber optics
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Network Protocols
A protocol is the set of rules and procedures
governing transmission across a network.
Ethernet is a common LAN protocol.
Transmission Control Protocol/Internet
Protocol (TCP/IP) is a file transfer protocol that can
send large files of information across sometimes
unreliable networks with assurance that the data will
arrive uncorrupted
The Four Layers of the TCP/IP Protocol
Packet Switching
Types of Network Processing
Client/server computing
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Peer-to-peer processing
• The first type of peer-to-peer (P2P) processing accesses unused CPU
power among networked computers.
• The second type of P2P is real-time, person-to-person collaboration.
• The third type of P2P is open-source, free, peer-to-peer file-sharing.
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Accessing the Internet
Cable Modem
Satellite
Wireless
Fiber to the Home
Source: © Mark Stay/iStockphoto)
Addresses on the Internet
IPv4
32 bits
IPv6
128 bits
Addresses on the Internet
Domain names consist of multiple parts,
separated by dots, which are read from right to left.
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Top-level domain the rightmost part of an
Internet name; common top-level domains are
.com, .edu, .gov
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Name of the organization the next section of
the Internet name
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Name of the specific computer the next section
of the Internet name
Internet Address example
www.business.auburn.edu
Name of the specific
computer: business
Name of the
organization:
Auburn University
Top level domain:
edu
The World Wide Web
• World wide web: A system of universally accepted
standards for storing, retrieving, formatting, and displaying
information via a client/server architecture.
• Not the same thing as the Internet
• Home page a text and graphical screen display that usually
welcomes the user and explains the organization that has
established the page.
• Uniform resource locator the set of letters that points to the
address of a specific resource on the Web.
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6.4 Network Applications
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Discovery
Communication
Collaboration
E-Learning
Telecommuting
Discovery
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Broswer Competitioin
Search engines
Metasearch engines
Discovery of material in foreign languages
Portals
Portals
- is a Web-based, personalized gateway to information and
knowledge that provides relevant information from different IT
systems and the Internet using advanced search and indexing
techniques.
• Commercial (public) portals- offer content for diverse
communities and are most popular portals on the Internet.
• Affinity portals support communities such as a hobby group
or a political party.
• Mobile portals are accessible from mobile devices
• Corporate portals offer a personalized single point of
access through a Web browser
• Industry wide portals for entire industries.
Communication
Electronic mail (e-mail)
Web-based call centers (customer call center)
Electronic chat room
Voice (VOIP, SKYPE)
Unified (integrates voice, fax, chat, location, etc.)
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Collaboration
Work group refers specifically to two or more
individuals who act together to perform some task.
Virtual group (team) is when group members are in
different locations.
Source: Howard Kingsnorth/The Image
Bank/Getty Images, Inc.
Collaboration
(continued)
• Virtual collaboration is the use of digital technologies that
enable organizations or individuals to collaboratively plan,
design, develop, manage and research products, services and
innovative applications.
• Workflow technologies facilitate the movement of
information as it flows through the sequence of steps that make
up an organization’s work procedures. Includes workflow
management and workflow systems
• Groupware refers to software products that support
groups of people who share a common task or goal and
who collaborate to accomplish it.
• Electronic Tele/Videoconferencing
• E-Learning and Distance Learning
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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Benefits of E-Learning
• Self-paced learning increases content retention.
• 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.
Drawbacks of E-Learning
• Instructors may need training to be able to teach
electronically.
• 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.
Telecommuting
Source: © Maria R.T. Deseo/PhotoEdit
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
Telecommuting Disadvantages
• For Employees
▫ Feelings of isolation
▫ No workplace visibility
▫ Potential for slower promotions
• For Employers
▫ Difficulties in supervising work
▫ Potential information security problems
▫ Additional training costs