1 Introduction to Information Technology Turban Rainer and
1 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks CHAPTER 6 TELECOMMUNICATIONS AND NETWORKS oleh : Kundang K Juman
2 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
3 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Chapter Overview Network Communication Telecommunications Networks Software Systems • 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 distributed processing • Open systems and enterprise networking • Electronic mail • Video conferencing • Electronic data interchange • Electronic funds transfer • Facsimile • Telecommuting • Distance learning
4 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Case : Network Management at Southwest Airlines The Business Problem î 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 î Network Health êto predict the possible ramifications of shifting network traffic êto virtually add and subtract applications and make theoretical changes in transmission capacity through-out the network êto help the network managers monitor network usage The Results î Save almost $100, 000 in staffing costs in the first year î Able to smooth network traffic among reservations centers î Shorten customers’ waiting time
5 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Case (continued…) What have we learned from this case? ? îRarely in modern companies do computers work in isolation îExchange of data - facilitated by telecommunications technologies - brings a number of very significant changes îTake management of resources very seriously îBring disastrous losses in revenues and customer satisfaction by minor disruption in telecommunications traffic îUnderstand technology in order to gain and maintain
6 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 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
7 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks The Telecommunications System (continued …) Computer Transmitter Communications Processor Communications Channels and Media Computer Network Software Receiver
8 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Communication Processors Modem îan analog network to carry voice signals or sounds in an analog wave format Multiplexer îan electronic device that allows a single communications channel to carry data transmissions simultaneously from many sources Front-end-Processor îa small secondary computer dedicated solely to communication in computer system
9 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Communication Media and Channels Cable Media îTwisted-pair wire îCoaxial cable êbase band transmission êbroad band transmission îFiber optics êoptical networking Copper versus fiber îthe price differential between copper (cheap) and fiber (expensive) is beginning to narrow
10 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Communication Media and Channels (continued …) Wireless Media îMicrowave - transmission stations : usually not spaced more than 30 miles apart îSatellite - digital transmission êGeostationary earth orbit (GEO) - 22, 300 miles êMedium earth orbit (MEO) - 6, 000 miles êLow earth obit (LEO) - 400 to 1, 000 miles êGlobal positioning system - 10, 900 miles îRadio êuse when you do not have to depend on microwave or satellite links, especially for short ranges
11 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Communication Media and Channels (continued …) Wireless Media (continued. . . ) îInfrared êred light not commonly visible to human eyes êcommonly used in television or videocassette remote control units îCellular radio technology êtransfers calls from one cell to another îMobile computing êoccurs on Radio-based networks that transmit data to and from mobile computers îPersonal communication services êuses lower-power and higher-frequency means
12 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Communication Media and Channels (continued …) Characteristics of Communications Media îTransmission speed êBandwidth - range of frequencies available îBaud rate êMeasured in bits per second (bps) îTransmission mode êAsynchronous or Synchronous
13 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Telecommunications Carriers Common Carriers îthe long-distance telephone companies Value-added Carriers îhave developed private telecommunications systems and provide services for a fee Switched Lines îa person can access from his or her computer to transmit data to another computer Dedicated îprovide a constant connection between two devices and require no switching or dialing
14 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Telecommunications Services Wide-area Telecommunications Services (WATS) îmethod for billing customers who use voice band media extensively Telephone and Dialing Services îAutomatic Number Identification (ANI) Integrated Services Digital Network (ISDN) îtransfer voice, video, image, and data simultaneously Digital Subscriber Line (DSL) îprovide high-speed, digital data transmission
15 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Local Area Network (LAN) - connect two or more communicating devices within 2, 000 feet îLAN Technology êthe network gateway connects the LAN to public networks or other corporate networks so that the LAN can exchange information with networks external to it îPrivate Branch Exchanges (a type of LAN) êcontrols telephone switching at a company site êcarry both voice and data êperform call waiting, call forwarding, and voice mail
16 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Network Typologies Star network Bus network Hierarchical network Ring network Minicomputers Desktop computers Mainframe
17 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks (continued …) Wide Area Network (WAN) - long-haul, broadband (analog) networks covering wide geographic area îValue-added Networks (VANs) êprivate, data-only networks êadd message storage, tracking, and relay services as well as teleconferencing services îVirtual Private Networks (VPNs) êallow an organization to leverage the robust, shared communication infrastructure of the internet êprovide a gateway between a corporate LAN and the Internet êallow access to a corporate network’s e-mail, shared files, or intranet, via an Internet connection
18 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Network Communications Software Network Operating Systems Network Management Software Protocols îset of rules and procedures governing transmission of data across a network îline access and collision avoidance îidentify each device in the communication path îexample : Ethernet 10 Base. T and Transmission Control Protocol/Internet Protocol (TCP/IP) îOpen System Interconnection (OSI)
19 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 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
20 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 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
21 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Types of Data Transmission Packet Switching îbreaks up blocks of text into small, fixed bundles of data called packets Fiber Distributed Data Interface (FDDI) îpasses data around a ring, but with a bandwidth of 100 Mbps Asynchronous Transfer Mode (ATM) îdivides data into uniform cells îeliminates the need for protocol conversion Switch Hub Technologies îturns many small LANs into one big LAN
22 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Network Processing Strategies Types of Organizational Distributed Processing îTerminal-to-Host Processing îFile Server Processing îClient/Server Architecture and Processing êlinks two or more computers in an arrangement êorganizations can make their systems faster and save money êfive models of client/server implementation that partition the three components between the server and the client
23 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Client/Server Configuration TYPES OF CLIENT/SERVER COMPUTING SEVERS: Distributed Presentation Remote Presentation Distributed Function Remote Data Management Data Management Function Presentation etwork N Presentation k r o w t e N Data Management Function Presentation Difficult More Difficult Extremely Difficult CLIENTS: Difficult k Networ Distributed Data Management
24 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 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.
25 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks Types of Organizational Distributed Processing Client/Server Architecture and Processing îPeer-to-peer processing êallows two or more computers to pool their resources êbenefits » 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
26 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 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 Embedded LAN Marketing Finance Embedded LAN Manufacturing Backbone wide area network Mainframe Corporate Backbone WAN (Fiber optic cables; FDDI protocol) Embedded LAN File server for backbone WAN Administrative Services and HRM Account -ing Embedded LAN
27 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
28 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 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
29 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks What’s in IT for Me? For Accounting îCorporate accountants perform cost/benefit analyses on the telecommunications infrastructure of the firm For Finance îFinancial managers use corporate networks to transfer and receive funds, complete transactions, and use EFT
30 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks What’s in IT for Me? (continued …) For Marketing îModern 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 îTelecommunications can make the linkage between the customer and the production function much more direct, making possible different manufacturing strategies
31 Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks What’s in IT for Me? (continued …) For Human Resource Management îHuman 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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