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Working Outside the Box

Understand the principles of telecommunications, the internet, and the World Wide Web. Learn about telecommunications carriers, distributed processing alternatives, and the challenges and solutions in communication.

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Working Outside the Box

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  1. Working Outside the Box

  2. Basic Concepts • Telecommunications Basics  • The Internet, a network of networks  • The World-wide-web, an Internet implementation  • Serious Issues   MIS 300, Chapter 4

  3. Principles and Learning Objectives -1 • Effective communications are essential to organizational success.  • Define the term telecommunications and describe the function of the components of a telecommunications system. • Identify the three types of telecommunications carriers and discuss the services they provide. • Name three distributed processing alternatives and outline their basic features. MIS 300, Chapter 4

  4. Principles and Learning Objectives -2 • The Internet is like many other technologies—it provides a wide range of services, some of which are effective and practical for use today, others are still evolving, and still others will fade away from lack of use.  • Briefly describe how the Internet works, including alternatives for connecting to it and the role of Internet service providers. MIS 300, Chapter 4

  5. Principles and Learning Objectives -3 • Originally developed as a document-management system, the World Wide Web is a menu-based system that is easy to use for personal and business applications.  • Describe the World Wide Web and the way it works, including the use of Web browsers, search engines, and other Web tools. MIS 300, Chapter 4

  6. Principles and Learning Objectives -4 • Because the Internet and the World Wide Web are becoming more universally used and accepted for business, management, service, and speed, privacy and security issues must continually be addressed and resolved.  • Identify and briefly describe the applications associated with the Internet and the Web. • Define the terms intranet and extranet and discuss how organizations are using them. • Identify several issues associated with the use of networks. MIS 300, Chapter 4

  7. An Overview of Telecommunications and Networks • Telecommunications: the electronic transmission of signals for communications • Telecommunications medium: anything that carries an electronic signal and interfaces between a sending device and a receiving device • Telecommunications carrier: any business that provides (leases, services) telecommunications media. • Telecommunications service: any service to customers at least partially facilitated by telecommunications MIS 300, Chapter 4

  8. Expression Interpretation Encoding Decoding Communication Model Meaning-2 Meaning-1 Sender Channel Receiver M e s s a g e Challenges: 1. Various processes2. Will meanings match?3. Why encode?4. Purpose? Intention? MIS 300, Chapter 4

  9. Characteristics of Communication • Encoding/decoding scheme • Speed of transmission (baud) • Directionality (one-way, bidirectional, switchable) • Noise • Equivocation (loss of signal) • Ambiguity (loss of meaning) • Turntaking (protocol) MIS 300, Chapter 4

  10. The Telecommunications Problem Sender Channel Receiver Encoding Decoding Distance: Sender and Receiver are not in direct contactEquivocation: Message loses power over distanceNoise: Channel introduces unwanted messageCoordination: It’s not clear what a message event is MIS 300, Chapter 4

  11. Solutions to the problems Sender Channel Receiver Encoding Decoding Distance: Long “wires” of various typesEquivocation: Boosting of power (introduces noise)Noise: Special encoding schemesCoordination: Coordination messages (protocols) Notice: Nothing about meaning, intention MIS 300, Chapter 4

  12. Basic Economics • Sources aren’t “on” all the time • Sources make mistakes; repetition is dangerous and costly • Channels are usually relatively expensive • Sharing channels is a good use of an expensive resource; sharing is costly • All channels are error-prone; the way to compensate is redundancy • The more complex the scheme, the higher the cost and the more likely is failure or error. MIS 300, Chapter 4

  13. What Is a Signal? ANALOG signal: strength is proportional to “content” • A communication event • Has a definite start and stop • Carries information (which is NOT the signal) DIGITAL signal: strength is fixed at either 0 or a constant 1 0 1 1 1 0 1 0 0 MIS 300, Chapter 4

  14. Inside a Digital Signal The bits that form part of the byte may be ones (at or above a certain level) or zero (below this level). This byte is 1011 0110 (1’s in color) Beginning of byte has special “bit” called a start bit Ending of byte has special “bit” called a stop bit MIS 300, Chapter 4

  15. What Is the Advantage of Digital Signalling? • First, simplicity, only two signal levels • Second, resistance to noise • Third, amplification can work without amplifying noise • Fourth, potential to add check bits to reconstruct byte in the event of errors (for example, parity checking). MIS 300, Chapter 4

  16. Over distance, signal weakens Noise intrudes …and sent on its way again Signal is “clipped” at threashold level …and then amplified Amplification “On” threashold Original 0-1 MIS 300, Chapter 4

  17. The Equipment is Connected This is only what you see! Figure 4.1: Elements of a (Physical) Telecommunications System MIS 300, Chapter 4

  18. Transmission Media -1 Table 4.1: Telecommunications Transmission Media Types MIS 300, Chapter 4

  19. Transmission Media - 2 Table 4.1: Telecommunications Transmission Media Types MIS 300, Chapter 4

  20. Telecommunications Devices Table 4.2: Common Telecommunications Devices MIS 300, Chapter 4

  21. Carriers and Services • Local exchange carrier (LEC): a public telephone company in the United States that provides service to homes and businesses within its defined geographical area • Competitive local exchange carrier (CLEC): a company that is allowed to compete with the LECs, such as a wireless, satellite, or cable service provider • Long-distance carrier: a traditional long-distance phone provider, such as AT&T, Sprint, or MCI MIS 300, Chapter 4

  22. Carriers and Services (continued) Figure 4.3: Local Exchange Carriers MIS 300, Chapter 4

  23. Networks • Computer network: the communications media, devices, and software needed to connect two or more computer systems or devices • Network nodes: the computers and devices on the networks Node MIS 300, Chapter 4

  24. What Are Networks For? • At an electrical level, networks move electrons along paths between nodes • At a signal level, networks move coded characters along links connecting nodes • At a transportation level, networks move packages or packets of characters between source and destination along paths within the network • At a session level, networks move messages from sender to receiver. • At the application level, networks move information from a server to a client. Businesses can select various ways for this to happen. MIS 300, Chapter 4

  25. Basic Processing Strategies • Centralized processing: all processing occurs in a single location or facility • Decentralized processing: processing devices are placed at various remote locations • Distributed processing: computers are placed at remote locations but connected to each other via a network MIS 300, Chapter 4

  26. Terminal-to-Host, File Server, and Client/Server Systems • Connecting computers in distributed information processing: • Terminal-to-host: the application and database reside on one host computer, and the user interacts with the application and data using a “dumb” terminal • File server: the application and database reside on the one host computer, called the file server • Client/server: multiple computer platforms are dedicated to special functions, such as database management, printing, communications, and program execution MIS 300, Chapter 4

  27. Terminal-to-Host, File Server, and Client/Server Systems -2 Figure 4.6: Client/Server Connection MIS 300, Chapter 4

  28. Network Types • Personal area network (PAN) • Local area network (LAN) • Metropolitan area network (MAN) • Wide area network (WAN) • International network • Corrupt local area network (CLAN)  MIS 300, Chapter 4

  29. Network Types -2 Figure 4.7: A Typical LAN MIS 300, Chapter 4

  30. Network Types - 3 Figure 4.8: A Wide Area Network MIS 300, Chapter 4

  31. Communications Software and Protocols • Communications software: software that provides a number of important functions in a network, such as error checking and data security • Network operating system (NOS) • Network management software • Communications protocol: a standard set of rules that controls a telecommunications connection MIS 300, Chapter 4

  32. Packet Switching • Sender’s message is broken into (generally short, fixed-length) packets • Each packet is numbered and sent “into” the network • The network transmits the packets • The node assembles the packets in order (not an easy task) • The receiver gets the message from the node. MIS 300, Chapter 4

  33. Example of Packet Switching 456 Message FROM: Node 223 TO: Node 456 Count: 4 This is packet 1 This is packet 2 This is packet 3 This is packet 4 P3 P2 223 P4 P4 P1 P3 P2 Packet reassembly Transmission: each packet has its own path through the network P1 Costs Benefits Packet creation Better use of networkPacket handling Smaller unitsChance of error More even use of n/wRetransmissions Higher traffic Packet creation MIS 300, Chapter 4

  34. Use and Functioning of the Internet • Internet: a collection of interconnected networks, all freely exchanging information • ARPANET • The ancestor of the Internet • A project started by the U.S. Department of Defense (DoD) in 1969 • Internet Protocol (IP): communication standard that enables traffic to be routed from one network to another as needed MIS 300, Chapter 4

  35. How the Internet Works • The Internet transmits data from one computer (called a host) to another • If the receiving computer is on a network to which the first computer is directly connected, it can send the message directly • If the receiving computer is not on a network to which the sending computer is connected, the sending computer relays the message to another computer that can forward it MIS 300, Chapter 4

  36. How the Internet Works (continued) Figure 4.9: Routing Messages over the Internet MIS 300, Chapter 4

  37. How the Internet Works (continued) • Data is passed in chunks called packets • Internet Protocol (IP): communications standard that enables traffic to be routed from one network to another as needed • Transmission Control Protocol (TCP): widely used transport-layer protocol that is used in combination with IP by most Internet applications • Uniform Resource Locator (URL): an assigned address on the Internet for each computer MIS 300, Chapter 4

  38. Accessing the Internet • Connect via a LAN server • Connect via Serial Line Internet Protocol (SLIP)/Point-to-Point Protocol (PPP) • Connect via an online service • Other ways to connect MIS 300, Chapter 4

  39. Accessing the Internet (continued) Figure 4.10: Several Ways to Access the Internet MIS 300, Chapter 4

  40. Internet Service Providers • Internet service provider (ISP): 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  MIS 300, Chapter 4

  41. The World Wide Web • The Web, WWW or W3 • A menu-based system that uses the client/server model • Organizes Internet resources throughout the world into a series of menu pages, or screens, that appear on your computer • Hypermedia: tools that connect the data on Web pages, allowing users to access topics in whatever order they want MIS 300, Chapter 4

  42. The World Wide Web (continued) • Hypertext Markup Language (HTML): the standard page description language for Web pages • HTML tags: codes thatlet the browser know how to format the text on a Web page and whether images, sound, and other elements should be inserted MIS 300, Chapter 4

  43. The World Wide Web (continued) Figure 4.11: Sample Hypertext Markup Language MIS 300, Chapter 4

  44. Web Browsers • Web browser: software that creates a unique, hypermedia-based menu on a computer screen, providing a graphical interface to the Web • The menu consists of graphics, titles, and text with hypertext links • Ubiquitous and non-proprietary web browsers make it possible for the Internet to be a business platform. MIS 300, Chapter 4

  45. Search Engines • Search engine: a Web search tool • Examples: Yahoo.com, Google.com • Most search engines are free • Searches can use words, such as AND and OR, to refine the search MIS 300, Chapter 4

  46. Web Programming Languages • Java • An object-oriented programming language from Sun Microsystems based on C++ • Allows small programs (applets) to be embedded within an HTML document MIS 300, Chapter 4

  47. Web Services • Standards and tools that streamline and simplify communication among Web sites for business and personal purposes • Can also be used to develop new systems to send and receive secure messages between healthcare facilities, doctors, and patients, while maintaining patient privacy MIS 300, Chapter 4

  48. Internet and Telecommunications Services • E-mail and instant messaging • Instant messaging: a method that allows two or more individuals to communicate online, using the Internet • Internet cell phones and handheld computers • Career information and job searching • Web log (blog): a Web site that people can create and use to write about their observations, experiences, and feelings on a wide range of topics MIS 300, Chapter 4

  49. Internet and Telecommunications Services (continued) • Chat rooms: enable two or more people to engage in interactive “conversations” over the Internet • Internet phone and videoconferencing services • Content streaming: a method for transferring multimedia files over the Internet so that the data stream of voice and pictures plays more or less continuously without a break, or very few of them • Shopping on the Web MIS 300, Chapter 4

  50. Internet and Telecommunications Services (continued) • Web auctions • Music, radio, and video on the Internet • Other Internet services and applications MIS 300, Chapter 4

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