1. Foundations of information systems : BIS 1202 Lecture3 Telecommunications, Networks, and the Internet BIS12021

2. Learning Objectives  By the end of this lecture students should;  Identify and describe the fundamental components of a telecommunications system including media and hardware devices  Identify several network types and describe the uses and limitations of each  Name three basic processing alternatives for organizations that require two or more computer systems and discuss their fundamental features BIS12022

3. Learning Objectives  Understand how telecommunication has improved business  Factors affecting communication in telecommunications  Understand computer networks and protocols  Understand network hardware and how the internet works 3BIS1202

4. Telecommunications The communication of information by electronic means, usually over a distance. Telecommunications has improved business in three main ways: Better communication Higher efficiency Better distribution of data BIS11004

5. Telecommunications system A telecommunication system is a collection of compatible hardware and software arranged to communicate from one location to another. Essential components of a telecommunication system Computers-to process information Terminals or any input/output devices that send or receive data. Communication channels-links by which data or voice are transmitted between sending and receiving devices in a network BIS11005

6. Telecommunications system Essential components of a telecommunication system End processors which provide support functions for data transmission and reception E.g. modem and decoders Communications software, which controls input and output activities and manages other functions of the communications network 6BIS1202

7. Telecommunications in Daily Use Cellular Phones Videoconferences Voice Mail fax Web-Based Electronic Commerce Worldwide Peer-to-Peer File Sharing – Napster, Gnutella, Morpheus 7BIS1202

8. Communication Direction Simplex – One-way in one direction e.g. antenna Half-Duplex Systems that provide communications in both directions, but only one direction at a time. E.g. walkie talkies Full-Duplex-allows communication in both directions and allows this to happen simultaneously e.g. telephones 8 BIS1202

9. Communication Direction (Cont.) BIS11006/5/20169

10. Factors affecting Telecommunications Communications medium – Physical medium through which data can be communicated – Telephone lines, television cables Capacity – Speed at which data are communicated – Also called the transmission rate – It is often called “bandwidth”(the rate at which electronic signals can travel through a medium) Bandwidth is measured in bits per second (bps) – The greater the capacity, the faster the transmission BIS120210

11. Bandwidth and Media (Cont.) Bandwidth – Narrowband is low speed – Broadband has greater capacity Media – A medium is any means by which data can be transmitted 11BIS1202

12. Telecommunications Media Twisted Pair – Telephone line made of a pair of copper wires twisted to reduce electromagnetic interference (EMI) Coaxial Cable Commonly used for cable television transmission – More expensive than twisted pair – Greater transmission rate than twisted pair – Much less susceptible to EMI 12BIS1202

13. Telecommunications Media conts.. Microwaves : High-frequency, short radio- frequency (RF) waves – Terrestrial microwave – Satellite microwave Optical Fiber: – Fiber-optic technology uses light instead of electricity to transmit data 13BIS1202

14. Digital and Analog Data Analog data is represented as continuous waveforms – Example: audio tape Digital data is computer data – sequence of binary 0s and 1s: – Example: data stored on the hard drive 14BIS1202

15. Modulation (Cont.) 15BIS1202

16. Computer networks A computer network can be defined as: a communications system that links two or more computers and peripheral devices and enables transfer of data between the components’. Telecommunications: the communication of information by electronic means, usually over some distance. 16BIS1202

17. What is a Computer Network? Two or more computers or communications devices connected by transmission media and channels and guided by a set of rules for communication purposes that allow users to communicate with each other and share applications and data. Hardware:  Computer  Network card  Routers  Modem … Hardware:  Computer  Network card  Routers  Modem … Media:  Cable  Wire  Microwave … Media:  Cable  Wire  Microwave … Software:  Network OS  Utilities … Software:  Network OS  Utilities … Network Design: Logical layout Physical layout … Network Design: Logical layout Physical layout … Components of a Computer Network 6/5/2016BIS110017

18. Categorization of Networks.. A number of different ways exist to organize telecommunications components to form a network and hence provide multiple ways of classifying/categorizing a network By size: Local Area Networks (LANs) Wide Area Networks (WANs) Metropolitan Area Network (MAN) By capability: Client/Server Networks (Server-Based Networks)-Resources are shared with the help of a centralized computer Peer-to-Peer Networks –computers share equally with out having to rely on a server 18BIS1202

19. Client/Server Pros:  Very secure  Centralized servers easy to manage  Physically centralized  Secure OS  Better performance  Centralized backups  Reliability Cons:  Require professional administration  More hardware intensive 19 BIS1202

20. Peer-to-Peer (p2p) Computers on the network communicate with each others as equals and each computer is responsible for making its own resources available to other computers on the network. Pros:  Uses less expensive computer networks  Easy to administer  No NOS (network operating system) required  Shared resources – some machine will have what you need 20 BIS1202

21. Peer-to-Peer (p2p) Conts.. Cons:  Not very secure  Individual user performance easily affected  Tragedy of the commons – no guarantee others will administer their resources properly.  Hard to back up. 21BIS1202

22. Categories of Networks LANs (Local Area Networks) Networks within a building, or within a group of adjacent buildings(the interconnection of different network devices with in a small geographical area) WANs (Wide Area Networks) Networks that cross organizational boundaries or reach outside the company (The interconnection of different network devices with in a wide geographical area)  Metropolitan Area Network (MAN)  Covers a geographic area the size of a city or suburb. The purpose of a MAN is often to bypass local telephone companies when accessing long-distance service. 22BIS1202

23. Network Topologies One way of describing networks is by the way their components are connected, or topology. Physical layout of the nodes in a network – Star-consists of a central host computer connected to a number of smaller computers or terminals – Ring-each computer on a network can communicate directly with another computer-does not rely on a central host computer. – Bus-links a number of computers by a single circuit made of twisted wire, coaxial cable, or fiber optic cable – Tree-very many star networks interconnected together. 23BIS1202

24. Network Topology 24BIS1202

25. Network Selection Criteria  Size of the organization  Level of required security  Level of available administrative support  Amount of network traffic  Needs of the network users  Budget for building the network 25BIS1202

26. Networking Hardware Hub. device for connecting multiple twisted pair or fiber optic Ethernet devices together and making them act as a single network segment Switch. Interconnects different network devices together. Router.Interconnects networks based on different rules or protocols Network Interface Card (NIC). computer hardware component designed to allow computers to communicate over a computer network Bridge. A device that interconnects different network segments. 26BIS1202

27. Networks: Pros and Cons Resource sharing –Printers, CD-ROMs, computers.Software. Data and information sharing Communications- email. -voice and video. -E-learning. –VOIP. Reduced Cost On-line services Groupware –Software that supports group efforts over a network Electronic data interchange Security risks increase with networks Complexity is associated with networks Investment is high and return on it may not happen Pros Cons 27BIS1202

28. The Internet BIS11006/5/201628

29. The Internet A network of networks (interconnection of different networks for the purpose of sharing information and data) Popular uses – E-mail – Instant messaging – Browsing the World Wide Web – Newsgroups and chat rooms 29BIS1202

30. Internet Service Providers Any company that provides individuals or organizations with access to the Internet Most charge a monthly fee Many ISPs and online services – Offer broadband Internet access through digital subscriber lines (DSLs), cable, or satellite transmission 30BIS1202

31. Network Protocols Communication protocols – Rules governing the communication between computers or between computers and other computer-related devices Network protocols-Rules governing a network of devices 31 BIS1202

32. Protocols (Cont.) LAN Protocols Ethernet Token passing WAN Protocols OSI (Open Systems Interconnection) Standard protocol model Seven layers 32BIS1202

33. Summary Telecommunications concepts and terminology Communication within a computer system and among computers Telecommunications media and devices Network layouts and protocols Telecommunications impact on operations Telecommunications developments and speed 33BIS1202

34. Review questions List major components of a computer and explain their functions Explain how computers communicate Classify computers into major categories, and identify their strengths and weaknesses With examples, Define the most commonly used hardware terminology. Input devices Output devices Memory Cache memory EPROM 34BIS1202

35. questions (Cont.) Identify and evaluate key criteria when deciding what computers or related devices to purchase Explain the controversy regarding the health hazards of computers Evaluate hardware so that you can harness it to improve managerial processes Explain why successful managers must be familiar with telecommunications concepts and terminology Describe the principles of communication within a computer system and among computers Identify the major media and devices used in telecommunications differentiate between logical control unit and Arithmetic Logic Units 35BIS1202

36. questions (Cont.) How are networks used to solve business problems? List the main components of a network? Explain three main Network Topologies? Why do businesses use networks to share hardware? List and explain the functions of different network layouts and the concept of protocols Explain how telecommunications can improve operations in organizations List the types of transmission media that are available? 36