Transcript business and information technology

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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
CHAPTER 6
TELECOMMUNICATIONS
AND NETWORKS
oleh : Kundang K Juman
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Learning Objectives
 Describe the components of a telecommunications
system
 Describe the five basic types of communication
media, including their advantages and disadvantages
 Classify the major types of networks
 Differentiate among the three types of distributed
processing
 Identify seven telecommunications applications and
describe how they help the organization attain
competitive advantage
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Chapter Overview
Telecommunications
Networks
Network Communication
Systems
Software
• Signal
• Local area networks • Network operating system
•Communications
•Wide area networks
•Network management
processors
software
•Communications
•Protocols
media and channels
•Types of data transmission
•Communications
carriers and services
Network Processing
Telecommunications
Strategies
Applications
• Organizational
• Electronic mail
distributed processing
•Video conferencing
•Open systems and
•Electronic data interchange
enterprise networking
•Electronic funds transfer
•Facsimile
•Telecommuting
•Distance learning
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Case : Network Management
at Southwest Airlines
 The Business Problem
 it had to make the transition from its legacy
applications to client/sever
technology to maintain service levels and keep up with
network traffic volume
The Solution
 Network Health
 to predict the possible ramifications of shifting network traffic
 to virtually add and subtract applications and make theoretical
changes in transmission capacity through-out the network
 to help the network managers monitor network usage
The Results
 Save almost $100,000 in staffing costs in the first year
 Able to smooth network traffic among reservations centers
 Shorten customers’ waiting time
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Case (continued…)
What have we learned from this case??
 Rarely in modern companies do computers
work in isolation
 Exchange of data - facilitated by telecommunications
technologies - brings a number of very significant
changes
 Take management of resources very seriously
 Bring disastrous losses in revenues and customer
satisfaction by minor disruption in
telecommunications traffic
 Understand technology in order to gain and maintain
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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The Telecommunications System
 Hardware - all types of computers and communication
processors
 Communications media - the physical media through which
electronic signals are transmitted ,including wireless media
 Communications networks- the links among computers
and communications devices
 Communications software- software that controls the
telecommunications system and the entire transmission process
 Data communications providers- regulated utilities or
private firms that provide data communications services
 Communications protocols- the rules for transmitting
information across networks
 Communications applications- electronic data
interchange, teleconferencing, videoconferencing, electronic
mail, facsimile, and electronic funds transfer, as well as others
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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The Telecommunications System
(continued …)
Computer
Transmitter
Communications
Processor
Communications
Processor
Communications
Channels and Media
Computer
Network
Software
Receiver
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Communication Processors
Modem
 an analog network to carry voice signals or
sounds in an analog wave format
Multiplexer
 an electronic device that allows a single
communications channel to carry data
transmissions simultaneously from many sources
Front-end-Processor
 a small secondary computer dedicated solely to
communication in computer system
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Communication Media and Channels
Cable Media
 Twisted-pair wire
 Coaxial cable
 base band transmission
 broad band transmission
 Fiber optics
 optical networking
Copper versus fiber
 the price differential between copper (cheap) and
fiber (expensive) is beginning to narrow
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Communication Media and Channels
(continued …)
Wireless Media
 Microwave - transmission stations : usually not
spaced more than 30 miles apart
 Satellite - digital transmission




Geostationary earth orbit (GEO) - 22,300 miles
Medium earth orbit (MEO) - 6,000 miles
Low earth obit (LEO) - 400 to 1,000 miles
Global positioning system - 10,900 miles
 Radio
 use when you do not have to depend on microwave or
satellite links, especially for short ranges
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Communication Media and Channels
(continued …)
Wireless Media (continued ...)
 Infrared
 red light not commonly visible to human eyes
 commonly used in television or videocassette
remote control units
 Cellular radio technology
 transfers calls from one cell to another
 Mobile computing
 occurs on Radio-based networks that transmit
data to and from mobile computers
 Personal communication services
 uses lower-power and higher-frequency means
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Communication Media and Channels
(continued …)
Characteristics of Communications Media
 Transmission speed
 Bandwidth - range of frequencies available
 Baud rate
 Measured in bits per second (bps)
 Transmission mode
 Asynchronous or Synchronous
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Telecommunications Carriers
Common Carriers
 the long-distance telephone companies
Value-added Carriers
 have developed private telecommunications
systems and provide services for a fee
Switched Lines
 a person can access from his or her computer to
transmit data to another computer
Dedicated
 provide a constant connection between two
devices and require no switching or dialing
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Telecommunications Services
Wide-area Telecommunications Services (WATS)
 method for billing customers who use voice band
media extensively
Telephone and Dialing Services
 Automatic Number Identification (ANI)
Integrated Services Digital Network (ISDN)
 transfer voice, video, image, and data simultaneously
Digital Subscriber Line (DSL)
 provide high-speed, digital data transmission
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Networks
Local Area Network (LAN) - connect two or
more communicating devices within 2,000 feet
 LAN Technology
 the network gateway connects the LAN to public
networks or other corporate networks so that the LAN
can exchange information with networks external to it
 Private Branch Exchanges (a type of LAN)
 controls telephone switching at a company site
 carry both voice and data
 perform call waiting, call forwarding, and voice mail
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Network Typologies
Star network
Bus network
Hierarchical
network
Ring
network
Minicomputers
Desktop computers
Mainframe
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Networks (continued …)
Wide Area Network (WAN) - long-haul, broadband
(analog) networks covering wide geographic area
 Value-added Networks (VANs)
 private, data-only networks
 add message storage, tracking, and relay services as well as
teleconferencing services
 Virtual Private Networks (VPNs)
 allow an organization to leverage the robust, shared
communication infrastructure of the internet
 provide a gateway between a corporate LAN and the Internet
 allow access to a corporate network’s e-mail, shared files, or
intranet, via an Internet connection
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Network Communications Software
 Network Operating Systems
 Network Management Software
 Protocols
 set of rules and procedures governing
transmission of data across a network
 line access and collision avoidance
 identify each device in the communication path
 example : Ethernet10 BaseT and Transmission
Control Protocol/Internet Protocol (TCP/IP)
 Open System Interconnection (OSI)
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Seven Layers of the OSI Model
Transmits raw bits over a communication channel.
Its purpose is to provide a physical connection for
the transmission of data among network entities
and the means by which to activate and deactivate
a physical connection.
2) Data Link Provides a reliable means of transmitting data
across a physical link;break up the input data into
Layer
data frames sequentially and processes the
acknowledgement frames sent back by data into
data frames sequentially and processes the
acknowledgement frames sent back by the receiver
3) Network Routes information from one network computer to
another; accepts messages from source host and
Layer
sees to it that they are directed toward the
destination. Computers may be physically located
within the same network or within another network
that is interconnected in some fashion.
1) Physical
Layer
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Seven Layers of the OSI Model
(continued …)
Provides a network-independent transport service
to the session layer, accepts data from session
layer, splits it up into smaller units as required,
passes these to the network layer, and ensures all
pieces arrive correctly at other end.
Provides user’s interface into network; where
5) Session
user must negotiate to establish connection with
Layer
process on another machine. Once the connection
is established, the session layer can manage the
dialogue in an orderly manner.
6) Presentation Translates message to and from the format used
in the network to a format used at the application
Layer
layer
7) Application Includes activities related to users, such as
supporting file transfer, handling messages, and
Layer
providing security.
4) Transport
Layer
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Types of Data Transmission
Packet Switching
 breaks up blocks of text into small, fixed bundles of
data called packets
Fiber Distributed Data Interface (FDDI)
 passes data around a ring, but with a bandwidth of
100 Mbps
Asynchronous Transfer Mode (ATM)
 divides data into uniform cells
 eliminates the need for protocol conversion
Switch Hub Technologies
 turns many small LANs into one big LAN
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Network Processing Strategies
Types of Organizational Distributed
Processing
 Terminal-to-Host Processing
 File Server Processing
 Client/Server Architecture and Processing
 links two or more computers in an arrangement
 organizations can make their systems faster and
save money
 five models of client/server implementation that
partition the three components between the server
and the client
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Client/Server Configuration
TYPES OF CLIENT/SERVER COMPUTING
SEVERS:
Distributed
Presentation
Remote
Presentation
Distributed
Function
Remote
Data
Management
Data
Management
Data
Management
Data
Management
Data
Management
Function
Function
Function
Distributed
Data
Management
Data
Management
Presentation
Data
Management
Presentation
Function
Function
Function
Presentation
Presentation
Presentation
Presentation
Difficult
More
Difficult
More
Difficult
Extremely
Difficult
CLIENTS:
Difficult
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Benefits and Limitations of Client/Server
Architecture for Network Processing
Benefits
Limitations
 The network is not overloaded
with entire files being
transferred back and forth
 File integrity is much easier to
maintain because only the server
actually updates the files. File
security easier to maintain with
server in full control of file data
 Microcomputers with
independent processing power
are more difficult to coordinate
and administer on a network.
 There is difficulty in writing
software that divides processing
among clients and servers.
 Specific servers can be slowed
when too many clients need
service.
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Types of Organizational
Distributed Processing
Client/Server Architecture and Processing
 Peer-to-peer processing
 allows two or more computers to pool their
resources
 benefits
» there is no need for a network administrator
» the network is fast and inexpensive to set up
and maintain
» each computer can provide backup copies of
its files to other computers for security
» it is the easiest network to build
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Open Systems and Enterprise
Networking
Open Systems - allows any computing device to be
seamlessly connected to and interact with any other computing
device, regardless of size, operating system, or application
Connectivity - ability of the various computer resources to
communicate with each other through network devices
Enterprise-wide Network
File server for
backbone
WAN
Backbone wide
area network
Embedded
LAN
Marketing
Finance
Embedded
LAN
Manufacturing
Mainframe
Corporate Backbone
WAN
(Fiber optic cables;
FDDI protocol)
Embedded
LAN
Administrative
Services
and HRM
Account
-ing
Embedded
LAN
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
Telecommunications Applications
Electronic Mail (e-mail) - computer-based
messages transmitted through telephone wires or
wireless networks
Videoconferencing - allows people to have “face-toface” communications with a group in another location
Electronic Data Interchange (EDI) - electronic
transmission of routine, repetitive business documents
directly between the computer systems
Electronic Funds Transfer (EFT) - electronically
routing funds, debits and credits, and charges and
payments
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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Telecommunications Applications
(continued …)
Facsimiles (FAX) - convert modulated signals
into white and black areas for printing
Telecommuting - work at home, using personal
computers and telecommunications technology to
communicate via electronic mail with other
workers, and to send and receive business work
Distance Learning - the students are able to see
and hear the professor, and the professor can hear
the students off-site; students may be able to see
each other
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
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What’s in IT for Me?
For Accounting
 Corporate accountants perform cost/benefit
analyses on the telecommunications
infrastructure of the firm
For Finance
 Financial managers use corporate networks to
transfer and receive funds, complete
transactions, and use EFT
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
What’s in IT for Me? (continued …)
 For Marketing
 Modern telecommunications technologies open
huge conduits of information to and from an
organization, and provide great strategic
advantage to the marketing function
For Production/Operations Management
 Telecommunications can make the linkage
between the customer and the production
function much more direct, making possible
different manufacturing strategies
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 6 Telecommunications and Networks
What’s in IT for Me? (continued …)
 For Human Resource Management
 Human resource managers utilize their
corporate networks extensively for posting
job openings, and use internal corporate
networks to publish corporate policies,
company newsletters and job openings