Transcript Supply Chain Enterprise Resources Planning and Business

Technology Guide 4
Telecommunications
and
the Internet
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IT for Management
Prof. Efraim Turban
Telecommunication Concepts
• Telecommunication
– long-distance communication through the
use of common carriers, including
telephone, television, and radio.
• Data Communications
– Electronic collection, exchange, and
processing of data or information,
including text, pictures, voice, and other
information that is digitally coded and
intelligible to a variety of electronic
machines
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IT for Management
Prof. Efraim Turban
Telecommunication System
Host
Computer Hardware
Host
Computer
PC or
Terminal
PC or
Terminal
Front end
processor
Telecommunication
media
Multiplexor
Multiplexor
(channels)
Receiver
Modem
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Modem
IT for Management
Prof. Efraim Turban
Electronic Signals
• Analog Signals
– continuous waves that “carry” information
by altering the characteristics of the waves
– amplitude and frequency
• Digital Signals
– discrete on-off pulses that convey
information in terms of 1s and 0s, just like
the central processing unit in computers
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IT for Management
Prof. Efraim Turban
Database and
Database Management Systems
• Database
– an organized logical grouping of related files
– no data redundancy, data isolation, and data
inconsistency
• Database Management Systems (DBMS)
– a program that provides access to a database
– permits an organization to centralize data,
manage them efficiently, and provide access
to the stored data by application programs
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IT for Management
Prof. Efraim Turban
Communication Processors
• Modem
– Performs modulation and
demodulation
– Modulation convert information
from digital to analog
– Demodulation convert information
form analog to digital
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IT for Management
Prof. Efraim Turban
Communication Processors
• Multiplexor
– An electronic device that allows a single
communications channel to carry data
transmissions simultaneously from
many sources
• Front-end Processor
– A specialized computer that managers
all routing communications with
peripheral devices
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IT for Management
Prof. Efraim Turban
Communications Media
(Channels)
• Cable Media
– Twisted-pair wire consists of strands of copper wire
twisted in pairs
– Coaxial cable consists of insulated copper wire, and
is much less susceptible to electrical interference and
can carry much more data than twisted-pair wire
– Fiber Optics consists of thousands of very thin
filaments of glass fibers
– Photonics generates and harnesses light and other
forms of radiant energy whose quantum unit
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IT for Management
Prof. Efraim Turban
Communications Media
(Channels)
• Wireless Media
– Microwave
– Satellite
• geostationary earth orbit (GEO);
medium earth orbit (MEO); and low
earth orbit (LEO)
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– Global Positioning Systems
– Radio
– Infrared
IT for Management
Prof. Efraim Turban
Communications Media
(Channels)
• Wireless Media
– Cellular Radio Technology
• Wireless Application Protocol (WAP);
Wireless Markup Language (WML)
– Mobile Computer
– Personal Communication service
– Personal Digital Assistants
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IT for Management
Prof. Efraim Turban
Characteristics of
Communication Media
• Transmission Speed
– bandwidth : the range of frequencies available
in any communications channel
– bit per second (bps) : the unit of measurement
– channel capacity : narrowband, voiceband, and
broadband
– baud rate : the amount of data that can be
transmitted through a communications channel
• Optical Networking
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– dense wave division multiplexing (DWDM)
IT for Management
Prof. Efraim Turban
Transmission Direction
• Simplex Data Transmission
– uses only one direction only
• Half-duplex Transmission
– uses only one circuit, but it is used in
both directions
• Full-duplex Transmission
– uses two circuit for communications –
one for each direction simultaneously
T4-12
IT for Management
Prof. Efraim Turban
Transmission Mode
• Asynchronous Transmission
– only one character is transmitted or received
at a time
– inherently inefficient
• Synchronous Transmission
– a group of characters is sent over a
communications link in a continuous bit
stream while data transfer is controlled by a
timing signal initiated by the sending device
T4-13
IT for Management
Prof. Efraim Turban
Transmission Accuracy
• Telephone line cables may be mishandled
by repair personnel, accidentally cut by
construction workers, or subjected to
power surges while data are being
transmitted.
• Accuracy controls consist of bits called
parity bits that are like check sums aded to
characters and/or blocks of characters at
the sending end of the line.
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IT for Management
Prof. Efraim Turban
Protocols
• Protocol is a set of rules and
procedures governing transmission
across a network
• Transmission Control
Protocol/Internet Protocol (TCP/IP)
is a file transfer protocol that can
send large files of information n
across sometimes unreliable
networks with assurance that he
data will arrive in uncorrupted form
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IT for Management
Prof. Efraim Turban
Communication Standards
• Network Standards
– physical layer, data link layer, network layer,
transport layer, session layer, presentation layer, and
application layer
– System Network architecture (SNA) standard
• Transmission Standards
– fiber distributed data interface (FDDI), asynchronous
transfer mode (ATM), switch hub technologies, and
Integrated services digital network (ISDN)
• Software Standards
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– Operating systems, graphical user interface standard,
software application standards
IT for Management
Prof. Efraim Turban
Interfaces
• Parallel Data Transfer
– most often used for local communication, employs
a communications interface with a series of
dedicated wires, each serving one purpose
– both data and control signals are transmitted
simultaneously
• Serial Data Transfer
– most often used for long-distance communications,
is bit by bit rather than many bits in parallel
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IT for Management
Prof. Efraim Turban
Network Topology
• Bus Network
– nodes are arranged along a single length of
twisted-pair wire, coaxial cable, or fiber optic
cable that can be extended at he ends
• Rink Network
– nodes are arranged along the transmission path
so that a signal passes through one station at a
time before returning to its originating node
• Star Network
– a central node that connects to each of the other
nodes by a single, point-to-point link
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IT for Management
Prof. Efraim Turban
Local Area Networks (LAN)
• LAN connects two or more communicating
devices within a short distance
– Gateway is a communications processor that
can connect dissimilar net works by translating
for one set of protocols to another
– Bridge connects two networks of the same type
– Router routes messages through several
connected LANs or to a WAN
• Private Branch Exchange (PBX)
T4-19
IT for Management
Prof. Efraim Turban
Wide Area Networks (WANs)
• Value-Added Networks (VAN)
– private, multipath, data-only, third-partymanaged networks that can provide economies
in the cost of service and network management
• Frame Relay
– a shared network service that packages data into
“frames” that are similar to packets
• Virtual Private Network (VPN)
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– a set of hardware and software that provides a
gateway between a corporate LAN and the
internet
IT for Management
Prof. Efraim Turban
Network Processing
• Point-to-Point Connection
– two devices on a network are
directly connected
• Peer-to-Peer Connection
– two devices have the same relative
standing, as with two
microcomputers
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IT for Management
Prof. Efraim Turban
Client/Server Architecture
• Presentation Component
– the application interface or how the
application appears to the user
• Applications Logic
– created by the business rules of the
application
• Data Management Component
– consists of the storage and management
of the data needed by the application
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IT for Management
Prof. Efraim Turban
Types of
Client/Server Architecture
• Distributed Presentation
• Remote Presentation
• Distributed Function
• Remote Data Management
• Distributed Data Management
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IT for Management
Prof. Efraim Turban
Peer-to-Peer Architecture
• Network information is stored on a
centralized file server and made available
to ma clients, the Information stored
across peer-to-peer networks is uniquely
decentralized.
• Popular peer-to-peer network operating
systems include Microsoft’s Windows 95
and 98, Windows NT, Artisoft’s
LANtastic, and Netware Lite.
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IT for Management
Prof. Efraim Turban
Open Systems and
Enterprise Networking
• Connectivity
– the ability of the various computer resources to
communicate with each other through network devices
without human intervention
• Portability
– the ability to move applications, data, and even people
form one system to another with minimal adjustments
• Interoperability
– the ability of systems to work together by sharing
applications, data, nd computer resources.
• Scalability
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– the ability to run applications unchanged on any open
system where the hardware can range form a laptop
PC to a supper computer
IT for Management
Prof. Efraim Turban
Open Systems and
Enterprise Networking
• Embedded LANs
– open systems and connectivity have
enabled networks to completely span
organization
– Most firms have multiple LANs and
may have multiple WANs, which are
interconnected to form an
enterprisewide network
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IT for Management
Prof. Efraim Turban
Internet
• Basic Characteristics and Capabilities
– Accessing the Internet
• access an internet-connected file server on
your organization’s LAN
• log into the Internet from your home
• wireless connections
– TV as a channel to the Internet
• a special connection device, and a
telephone connection
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IT for Management
Prof. Efraim Turban
Internet
• The TCP/IP Protocol
– procedures and rules for transferring data
across the internet
• Internet Resources
– access libraries and conduct research
– access to large databases
– access to online magazines
• Wide Area Information Servers (WAIS)
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– an Internet directory designed to help end users
find and retrieve information over the networks
by providing efficient search methods
IT for Management
Prof. Efraim Turban
Internet
• The World Wide Web
– a vast connection of interconnected pages of
information that are stored on computers around
the world that are connected to the internet
• Bowser
– a set of standards for storing, retrieving,and
manipulating information
• Hyperlinks
– links to internal or external documents
• Web Site : a computer network
• Web Page : a document
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IT for Management
Prof. Efraim Turban
Internet
• Creating Web Documents
– HyperText Markup Language (HTML)
– Java
• Search Engines
– enable you to locate information by using
key words in the same way that you
would search online library resources
• Internet Addresses
– uniform resource locator (URL)
– hypertext transfer protocol (HTP)
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IT for Management
Prof. Efraim Turban
Internet
• Gopher
– a “burrowing tool” that provides access to a
wide range of textual information available
on the Internet
• Downloading Software and Files
– cheapware, freeware, and shareware
– file transfer protocol (FTP)
• Electronic Mall (e-mall)
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– allows multiple-access communication
delivered exclusively on a computer network
IT for Management
Prof. Efraim Turban
Internet
• Chat Programs
– allow you to send messages to people at the same time
• Newsgroup
– organized in a directory and are divided into
categories and subcategories
• Mailing Lists
– subscribe : add e-mail name and address
– unsubscribe : remove the e-mail name and address
• Electronic Bulletin Boards
– allow people leave messages for other people and
receive massive amounts of information
• Portals
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– a Web site designed to offer Internet services
IT for Management
Prof. Efraim Turban
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