Introduction to Information Technology Turban, Rainer and Potter Chapter 6

Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks

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

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Classify the major types of networks

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Differentiate among the three types of distributed processing

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Identify seven telecommunications applications and describe how they help the organization attain competitive advantage

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Chapter Overview Telecommunications Networks Systems • Signal • Local area networks •Communications •Wide area networks processors •Communications media and channels •Communications carriers and services

Network Communication Software • Network operating system •Network management software •Protocols •Types of data transmission

Network Processing Strategies

Telecommunications Applications

• Organizational distributed processing •Open systems and enterprise networking

• Electronic mail •Video conferencing •Electronic data interchange •Electronic funds transfer •Facsimile •Telecommuting


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

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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

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The Results Save almost $100,000 in staffing costs in the first year Able to smooth network traffic among reservations centers

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Case (continued…) What have we learned from this case??

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Rarely in modern companies do computers work in isolation Exchange of data - facilitated fa cilitated by telecommunications technologies brings a number of very significant changes Take management of resources very seriously

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Bring disastrous losses in revenues and customer satisfaction by minor disruption in telecommunications traffic

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Understand technology in order to gain and maintain competitive advantage

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The Telecommunications System Hardware - all types of computers and communication processors

Communications media - the physical media through which

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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

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The Telecommunications System (continued …)

Computer

Transmitter

Communications Processor

Communications Processor

Communications Channels and Media

Computer Network Software

Receiver


Communication Communica tion Processors Modem an analog network to carry voice signals or sounds in an analog wave format

Multiplexer

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an electronic device that allows a single communications channel to carry data transmissions simultaneously from many sources

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Front-end-Processor

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a small secondary computer dedicated solely to communication in computer system

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Communication Communica tion Media and Channels Cable Media Twisted-pair wire Coaxial cable

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base band transmission broad band transmission

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Fiber optics

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optical networking

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Copper versus fiber

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the price differential between copper (cheap) and fiber (expensive) is beginning to narrow

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Communication Communica tion Media and Channels (continued …) Wireless Media Microwave - transmission stations : usually not spaced more than 30 miles apart Satellite - digital transmission

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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

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Radio

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use when you do not have to depend on microwave or satellite links, especially for short ranges

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Communication Communica tion 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

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Cellular radio technology

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transfers calls from one cell to another

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Mobile computing

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occurs on Radio-based networks that transmit data to and from mobile computers

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Personal communication services

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uses lower-power and higher-freq higher-frequency uency means

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Communication Communica tion Media and Channels (continued …) Characteristics of Communications Media Transmission speed Bandwidth - range of frequencies available

Baud rate

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Measured in bits per second (bps)

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Transmission mode

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Asynchronous or Synchronous

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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

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Switched Lines a person can access from his or her computer to transmit data to another computer

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Dedicated provide a constant connection between two devices and require no switching or dialing

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Telecommunications Services Wide-area Telecommunications Services (WATS) method for billing customers who use voice band media extensively

Telephone and Dialing Services

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Automatic Number Identification (ANI)

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Integrated Services Digital Network (ISDN)

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transfer voice, video, image, and data simultaneously

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Digital Subscriber Line (DSL)

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provide high-speed, digital data transmission

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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)

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controls telephone switching at a company site carry both voice and data perform call waiting, call forwarding, and voice mail

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Network Typologies Star network

Bus network

Hierarchical network Ring network

Minicomputers

Mainframe


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 teleconferencin g services

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Virtual Private Networks (VPNs)

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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 access to a corporate network’s e-mail, e-mail, shared files, files, or intranet, via an Internet connection

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Network Communications Software Network Operating Systems 

Network Management Software

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Protocols set of rules and procedures governing transmission of data across a network line access and collision avoidance

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identify each device in the communication path

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example : Ethernet10 BaseT and Transmission Control Protocol/Internet Protocol (TCP/IP (TCP/IP))

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Open System Interconnection (OSI)

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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 1) Physical Layer


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 co nnection with Layer process on another another machine. machine. Once the connection is established, the session layer can manage the t he 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


Types of Data Transmission Packet Switching breaks up blocks of text into small, fixed bundles of data called packets

Fiber Distributed Data Interface (FDDI)

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passes data around a ring, but with a bandwidth of 100 Mbps

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Asynchronous Transfer Mode (ATM)

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divides data into uniform cells eliminatess the need for protocol conversion eliminate

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Switch Hub Technologies

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turns many small LANs into one big LAN


Network Processing Strategies Types of Organizational Distributed Processing Terminal-to-Host Processing File Server Processing

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Client/Server Architecture and Processing

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links two or more computers in an arrangement organizations can make their systems faster and save money

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five models of client/server implementation that partition the three components between the server and the client

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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

Presentation

r k Ne t wo

Presentation

CLIENTS:

r k Ne t wo

r k Ne t wo

Presentation

Distributed Data Management Data Management

r k Ne t wo Data Management

Function

Function

Function

Presentation

Presentation

Presentation

More

More

Extremely


Benefits and Limitations of Client/Server Architecture for Network Processing Limitations

Benefits 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 Microcomputers processing power are more difficult to coordinate and administerr on a network. administe 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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Types of Organizational Distributed Processing Client/Server Architecture and Processing Peer-to-peer processing allows two or more computers to pool their resources benefits

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» 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


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

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communicate with each other through network devices

Enterprise-wide Network

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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


Telecommunications Applications Electronic Mail (e-mail) - computer-based messages transmitted through telephone wires or wireless networks

Videoconferencing - allows people to have “face-to-face”

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communications with a group in another location lo cation

Electronic Data Interchange (EDI) - electronic

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transmission of routine, repetitive business documents directly between the computer systems

Electronic Funds Transfer (EFT) - electronically routing

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funds, debits and credits, and charges and payments


Telecommunications Applications (continued …) Facsimiles (FAX) - convert modulated signals into white and black areas for printing

Telecommuting - work at home, using personal

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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

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the professor, and the professor can hear the students offsite; students may be able to see each other


What’s in IT for Me? For Accounting

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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


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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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

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Introduction to Information Technology Turban, Rainer and Potter Chapter 6

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