Transcript Telecommunications and Networks

Chapter 4:
Telecommunications and
Networks
Learning Objectives
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Identify business applications of
telecommunications and Internet
technologies.
Provide examples of the business value of
Internet, intranet, and extranet applications.
Learning Objectives (cont’d)
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Identify the basic components, functions, and
types of telecommunications networks used in
business.
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Explain the functions of major types of
telecommunications network hardware,
software, media, and services.
Real World Case 1 –
FedEx versus UPS
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Why does telecommunications play such a
key role in the competition between FedEx
and UPS?
Why does “information about the package”
have such a strategic business value in the
express delivery business?
Internet
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Internet is the most influential development
over the past two decades.
It is derived from the concept of
Internetworking, linking hundreds of
individual networks all over the world.
Frequently referred to as the “Net”.
The Internet is a global network of computer
networks linked together so that its users can
share data resources.
Internet
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The Internet provides instant and local access to an
amazing number of organizations, individuals, and
information resources.
No one owns the Internet and it has no formal
management organizations.
Originally the Internet was an initiative sponsored by
the Department of Defense to link its labs with
American universities.
The Internet does not have a central computer
system.
The Internet does not have a governing body.
How can we connect to the Internet?
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Even today individuals cannot connect directly to the
Net.
Anyone with a computer, a modem and a willingness
to pay a small monthly usage fee can access Internet
through an Internet Service Provider (ISP).
ISPs will provide you a username, password and
access phone number.
ISP is a commercial organization that offers Internet
access (AT&T) or online service (MSN, AOL).
World Wide Web
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Web is the Internet systems for hypertext linking, allowing users to
move from one Internet site to another.
It is a system with universally accepted standards for storing,
retrieving, formatting and displaying information.
Web pages are online documents that feature clickable hypertext links
that transport you to documents, graphics or other Web pages.
Internet browser softwares such as Netscape Navigator or Internet
Explorer enable end users to surf the Web.
Anyone using a Web browser can access any of millions of Websites.
To access a Web site the user must specify Uniform Resource Locator
(URL) which is the address of a specific resource on the Internet.
The URL for our university is http://www.cwu.edu.
http stands for hypertext transport protocol, which is the
communications standard to transfer pages on the Web.
Web sites are created by Web masters.
What are people doing on the Internet?
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E-mail: You can use e-mail to communicate with
your friends, to exchange messages.
Surf: You can browse websites and resources for
information, entertainment and e-commerce.
Chatting: Allows two or more people who are
simultaneously connected to the Internet to hold live,
interactive conversations. (Ex: Yahoo! Messenger)
What are the people doing on the
Internet?
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Discussion: Participating in discussions on thousands of topics.
Download: Allows to transfer data files, software, articles,
picture, music, video to your computer system.
Buy and sell: Buying and selling via e-commerce retailers,
wholesalers (Ex: E-bay).
Search for information: Several companies have created
directories of Web sites and their addresses, providing search
tools for finding information. Another tools, called search
engines can find Web sites. (Ex: Yahoo!, Google, Alta Vista).
Play games, watch TV, conduct free phone calls, listen to radio,
etc.
Business use of
the Internet
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The business value of the
Internet
E-commerce is the major
business use of the Internet.
For marketing, sales and
customer relationship
management applications,
applications in engineering
and human resources.
Enterprise communication
and collaboration
Forming new business
partnerships
Providing customer and
vendor support
Internet connection
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There are a number of ways that people can connect to the Internet. In
addition to traditional connections through plain old telephones and
modems, there are a number of high-speed alternatives.
Plain old telephone service: using phone line to connect the Internet.
Integrated Services Digital Network (ISDN): using existing twisted-pair
phone wires to provide high speed service.
Digital Subscriber Line (DSL): provides high speed over regular copper
telephone lines.
Cable Modems (TV lines): In some areas the company that provides
cable TV service also provides Internet service.
Satellite connections: In many regions of the world people can now
access the Internet via Satellite.
Cellular phones: There are Internet-enabled cellular phones from Sprint
and others, and small palm-top computers from Palm and others, that
give you Internet access nearly anywhere.
INTRANET
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An Intranet is a private and internal network using Web
technologies inside an organization.
It can be considered a private internal Web, which limits
viewing access to authorized users within the organization.
It enables employees to communicate, share information and
work together on common projects regardless of their physical
location.
Employees access information on the Intranet through a Web
browser. This information cannot be viewed by users outside the
organization. Thus it is separated from the visible, publicly
accessible Web.
It is protected by security measures such as passwords,
firewalls.
INTRANET
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Intranets require no special hardware. Intranet software technologies is the
same as that of the Web. The Web browsers and Web server software for
intranets are the same as those on the Web.
Ex: Hewlett Packard (HP) uses an intranet for many human resource
functions. The company’s 88,000 employees in 150 countries can access
HP’s intranet to fill out forms about beneficiaries, address changes, tax
withholdings, etc.
Ex: Boeing offers over 200,000 employees training via the Center of
Leadership and Training (CLT) intranet sites. It opens up the courses and
training opportunities for employees worldwide. By using the CLT intranet,
employees can choose from a wide range of course offerings.
EXTRANET
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Extranets are private intranets extended to authorized users
outside the company.
It is accessible to authorized outsiders.
Firms use such networks to coordinate their activities with
business partners, suppliers, customers for making purchases,
collaborating on design and other interorganizational work.
An extranet connects the intranets of two or more business
partners.
Extranets are useful for linking organizations with suppliers,
customers or business partners.
Extranets make customer and supplier access of intranet
resources a lot easier and faster than previous business methods.
Characteristics of The Internet, Intranet, and Extranet
FOCUS
TYPE OF
INFORMATION
USERS
ACCESS
The Internet
External
communications
General public
Any user with an
Internet
connection/public
and not restricted
The Intranet
Internal
Employees
Authorized
employees/private
and restriction
The Extranet
External
Business partners, Authorized
customers,
business
suppliers
partners/private
and restriction
Telecommunications Networks
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Communication is one of the most important of all human needs.
A business is a complex organization that relies on communication among its
employees to organize its internal activities and communicate with its
customers and suppliers to generate and sell its products and services.
Communication becomes even more important in a global environment.
Telecommunications is the communication of information by electronic
means.
It requires the following five steps:
Sender initiates message communication
Device puts sender’s message onto a telecommunications medium.
Telecommunications medium transfers message to receiver’s location
Device takes message off the communication medium
Recipient receives the message
Telecommunications capacity
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The capacity for information flow over a
telecommunications channel is called
bandwidth.
It is usually measured in bits/second.
Face-to-face bandwidth is simply limited by
how fast we can talk.
Communication among computer devices
usually occurs with much greater bandwidth.
Types of telecommunications networks
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We distinguish among different network types based
on the dimensions of communication: distance and
organizational context.
On the organizational context dimension networks are
called intranets if they serve a company’s employees,
extranets if they serve employees and partner
organizations.
Types of telecommunications networks
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On the distance dimension;
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Wide area networks (WAN) is a broad-band computer
network that spans a large geographical area (they serve
greater distance).
Used by multinational companies.
WANs transmit and receive information across cities
and countries.
Some WANs are commercial, regulated networks while
others are privately owned (Ex: AT&T or Sprint). Some
others are public in terms of their management,
resources and access. One such public WAN is the
Internet.
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Types of telecommunications networks
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Local Area Networks (LANs)- A LAN connects two or
more communicating devices within a short distance (One
building or several buildings in close proximity).
It allows all computer users to connect with each other to
share information and devices, such as printers.
In an office a LAN can give users fast and efficient access to
a common collection of information while also allowing the
office to pool resources, such as printers.
Metropolitan Area Networks (MANs)- They serve a large
city.
Types of telecommunications networks
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Virtual Private Networks (VPN): VPN is a private widearea network that connects an organization's LAN and
users to another through a public network, usually the
Internet.
A VPN provides long-distance connections virtually free of
direct charges.
A VPN handles the security and it uses the Internet as its
main network, but relies on firewalls and other security
features of its Internet and Intranet connections.
VNP is a means for allowing access to a private network’s
e-mail, shared files or intranet via an Internet connection.
Essential components of
Telecommunications Networks
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Computers
Terminals or any
input/output devices
Telecommunications
network software
Telecommunications
processors
Telecommunications
channels/media
Computers
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Telecommunications networks interconnect
computers of all sizes and types. They
include
Host computers (mainframes)
Front-end Processors (minicomputers)
Microcomputers
Terminals
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Terminals are any input/output devices that
use telecommunications networks to transmit
or receive data. They include:
Telephones
Personal computers
Network computers
Office equipment
Video terminals
Telecommunications network software
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Consists of programs that control telecommunications
activities and manage the functions of telecommunications
networks. They include network operating systems, Web
browsers, and programs.
Ex: Many operating systems such as Windows 2000/Server
provide a number of key network services. Allows network
managers to add or delete users and to specify their
permission to access to files, devices and services.
Ex: HP’s OpenView is a network management software. A
network analyst can perform many network management
functions.
Telecommunications processors
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Support data transmission and reception between
terminals and computers.
They include modems and switches.
A modem provides an interface between a computer
(or network) and the phone line, cable line (or
cellular connection).
Types of Signals: Analog and Digital
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Information travels through a telecommunications system in the form of
electromagnetic signals.
Signals are represented in two ways: analog and digital signals.
An analog signal is a continuous waveform that passes through a
communications medium; used for voice communications.
A digital signal is a discrete rather than continuous, waveform.
Most computers communicate with digital signals.
All digital signals must be translated into analog signals before they can be
transmitted in an analog system. The device that performs this translation is
called a modem (Modem is an abbreviation for
MOdulation/DEModulation).
A modem translates a computer’s digital signals into analog form for
transmission over ordinary telephone lines, or it translates analog signals
back into digital form for reception by a computer.
Telecommunications channels
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Telecommunications channels connect the
message source with the message receiver.
A channel can use different kinds of
telecommunications transmission media.
Telecommunications media physically link
the devices in a network.
They include twisted wire, coaxial cable, fiber
optics, terrestrial microwave, satellite and
other wireless transmission.
Telecommunications media
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Twisted pair
Consists of copper wire twisted in pairs.
It connects a telephone to its telephone jack in most
homes.
It is an older transmission medium.
Used to transmit analog phone conversations but can be
used for digital communication as well.
Relatively slow for transmitting data.
Inexpensive.
Widely available.
Telecommunications media
►Coaxial
cable
►Consists of thickly insulated copper wire.
►Used by cable TV companies, brings television signals
into the home.
►Can transmit large volumes of data quickly.
►Hard to wire in many buildings.
►Cannot support analog phone conversations.
►More expensive.
►Less common in buildings than twisted-pair wire.
Telecommunications media
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Fiber optics cable
Has the greatest capacity of the telecommunications media.
A fast, light and durable transmission medium.
Can transfer large volume of data.
More expensive, harder to install.
Many long-distance companies use it.
Can carry digital signals as well as analog signals.
SIGNAL
LASER
CABLE
PHOTO
DETECTOR
SIGNAL
Telecommunications media (cont’d)
Telecommunications media (cont’d)
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Wireless transmission sends signals through air or space
without being tied to a physical line. Common technologies
for wireless data transmission include;
Microwave:
Used for long-distance transmission.
uses the atmosphere as the medium through which to
transmit signals.
Can carry high-volume data.
Expensive.
Requires no cabling.
Telecommunications media (cont’d)
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Communication satellites:
The transmission of data using orbiting satellites.
Cost effective for transmitting large quantities of
data over very long distances.
Typically used for communications in large,
geographically dispersed organizations that would
be difficult to tie together through cabling media.
Very expensive.
Signals weaken over long distances.
It is useful for only 7-10 years.
ORBITING SATELLITES
MICROWAVE
TRANSMISSION
UPLINK
DOWNLINK
Telecommunications media (cont’d)
 3. Cellular phones: Work by using radio
waves to communicate with radio antennas
placed within adjacent geographic area
called cells. It transmits voice or data. It is
for mobile voice and data communications.
 4. Pagers: A wireless transmission
technology in which the pager beeps when
the user receives a message. Used to
transmit short alphanumeric messages.
The characteristics of telecommunications media
Twisted pairwire:
 least
expensive
Widely
available
Moderate
capacity
Easy to install
Transmit both
analog and
digital
Coaxial cable
Fiber optics
Microwave
moderately
expensive
Less common
in buildings
Moderate to
high capacity
Thick wires
Transmit
digital signal
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relatively
expensive
 longdistance
companies
use it
Very high
capacity
Difficult to
install
Transmit
both analog
and digital
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Cellular
Expensive
Limited
distance
Requires no
cabling
Provides
Best for high- mobile voice
volume long
Requires no
distance
cabling
Limited to
line-of-sight
Telecommunications Technology
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Organizations use diverse network technologies that
may or may not be compatible with the technologies of
other organizations.
So many different networks are interconnected
nowadays, they must have a common language or
protocol to communicate.
The protocol of the Internet is called Transmission
Control Protocol/Internet Protocol (TCP/IP).
Two computers using TCP/IP would be able to
communicate even if they were based on different
hardware and software platforms.