1. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 1 CHAPTER 6 TELECOMMUNICATIONS AND NETWORKS

2. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 2 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 3 Chapter Overview Telecommunications Systems Signal Communications processors Communications media and channels Communications carriers and services Networks Local area networks Wide area networks Network Communication Software Network operating system Network management software Protocols Types of data transmission Network Processing Strategies Organizational distributed processing Open systems and enterprise networking Telecommunications Applications 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 4 Case : Network Management at Southwest Airlines  The Business Problem  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  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 Results  Save almost $100,000 in staffing costs in the first year  Able to smooth network traffic among reservations centers  Shorten customers’ waiting time

5. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 5  What have we learned from this case?? Case (continued…)  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 competitive advantage  Rarely in modern companies do computers work in isolation

6. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 6 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 7 The Telecommunications System (continued …) Computer Communications Processor Communications Processor Computer Network Software Communications Channels and Media Transmitter Receiver

8. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 8 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

9. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 9 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

10. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 10 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

11. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 11 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

12. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 12 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

13. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 13 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

14. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 14 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

15. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 15 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

16. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 16 Network Typologies Star network Ring network Bus network Hierarchical network Mainframe Mini- computers Desktop computers

17. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 17 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

18. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 18 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)

19. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 19 Seven Layers of the OSI Model 1) Physical Layer 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 Layer Provides a reliable means of transmitting data across a physical link;break up the input data into 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 Layer Routes information from one network computer to another; accepts messages from source host and 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.

20. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 20 Seven Layers of the OSI Model (continued …) 5) Session Layer Provides user’s interface into network; where user must negotiate to establish connection with process on another machine. Once the connection is established, the session layer can manage the dialogue in an orderly manner. 6) Presentation Layer Translates message to and from the format used in the network to a format used at the application layer 7) Application Layer Includes activities related to users, such as supporting file transfer, handling messages, and providing security. 4) Transport Layer 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.

21. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 21 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

22. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 22 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

23. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 23 Client/Server Configuration TYPES OF CLIENT/SERVER COMPUTING SEVERS: Distributed Presentation Remote Presentation Distributed Function Remote Data Management Distributed Data Management Data Management Data Management Data Management Data Management Data Management Function Presentation Function Data Management Network CLIENTS: Difficult More Difficult More Difficult Extremely Difficult

24. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 24 Benefits and Limitations of Client/Server Architecture for Network ProcessingBenefits  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 dataLimitations  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 25 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

26. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 26 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 Manu- facturing Finance Marketing Account -ing Administrative Services and HRM Corporate Backbone WAN (Fiber optic cables; FDDI protocol) Mainframe Embedded LAN Embedded LAN Embedded LAN Embedded LAN Backbone wide area network File server for backbone WAN

27. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 27 Telecommunications Applications  Electronic Mail (e-mail) - computer-based messages transmitted through telephone wires or wireless networks  Videoconferencing - allows people to have “face-to- face” 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 28 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 29  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 What’s in IT for Me?

30. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 30 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

31. Introduction to Information Technology Turban, Rainer and Potter Chapter 6 Telecommunications and Networks 31 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