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Fundamentals of Information Systems, Second Edition 1 Telecommunications, the Internet, Intranets, and Extranets Chapter 4.

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Presentation on theme: "Fundamentals of Information Systems, Second Edition 1 Telecommunications, the Internet, Intranets, and Extranets Chapter 4."— Presentation transcript:

1 Fundamentals of Information Systems, Second Edition 1 Telecommunications, the Internet, Intranets, and Extranets Chapter 4

2 Fundamentals of Information Systems, Second Edition 2 Learning Objectives –Define the term telecommunications and identify and describe the function of the components of a telecommunications system. –Identify and briefly describe three basic data processing strategies, including their advantages and disadvantages.

3 Fundamentals of Information Systems, Second Edition 3 Learning Objectives –Briefly describe how the Internet works, including alternatives for connecting to it and the role of Internet service providers. –Identify and briefly describe common Internet services.

4 Fundamentals of Information Systems, Second Edition 4 Learning Objectives –Describe the World Wide Web and the way it works, including the use of Web browsers, search engines, Java, and other Web tools. –Define the terms intranet and extranet and discuss how organizations are using them. –Identify several control and management issues associated with the use of networks.

5 Fundamentals of Information Systems, Second Edition 5 Telecommunication –Electronic transmission of signals for communications –Telecommunications device is a hardware component that allows electronic communication to occur –Telecommunications medium carries an electronic signal and interfaces between a sending device and a receiving device

6 Fundamentals of Information Systems, Second Edition 6 Elements of a Telecommunications System

7 Fundamentals of Information Systems, Second Edition 7 Media Types (1) –Twisted-pair wire cable: Twisted pairs of copper wire Used in telephone service Slow transmission –Coaxial cable: Conductor wire is insulated Faster than twisted-pair –Fiber-optic cable: Thin strands of glass bound together Uses light beams Faster than coaxial cable

8 Fundamentals of Information Systems, Second Edition 8 Media Types (2) –Microwave transmission: High-frequency radio signal Must have unobstructed line of sight between sender and receiver Possible to intervene –Cellular transmission: Divide area into cells Each cell has a mobile telephone subscriber unit Possible to intervene –Infrared transmission: Signals as light waves

9 Fundamentals of Information Systems, Second Edition 9 Common Wiring and Cabling Types

10 Fundamentals of Information Systems, Second Edition 10 Common Telecommunications Devices –Modem: Translates data from digital form into analog form (for ordinary phones) and back MOdulation and DEModulation –Fax modem: Facsimile device but also a modem –Multiplexer: Allow several signals to be transmitted over the same line –PBX: Manages both voice and data transfer Switching equipment routes phone calls and messages within the building

11 Fundamentals of Information Systems, Second Edition 11 Carriers and Services Common carriers: Turk Telecom, AT&T Switched lines –Use switching equipment to connect one phone to another –Switch: Special purpose circuit that directs messages in certain directions Digital subscriber lines (DSL) –Use existing lines to transmit signals over 500Kbps –Faster Internet access

12 Fundamentals of Information Systems, Second Edition 12 Costs, Advantages, and Disadvantages of Several Line and Service Types Line/ServiceSpeedCost per month AdvantagesDisadvantages Standard phone line 56Kbps$10-40Broadly available Too slow ISDN64-128Kbps$50-150FasterNot available everywhere DSL500Kbps- 1.5Mbps $20-120Use standard line Expensive; not available ew. Cable modem 500Kbps- 1.5Mbps $20-120Use existing cable “” T Mbps$ FAST; used by corporations EXPENSIVE Satellite60-800Kps$30-120Instead of cable or DSL Expensive installation

13 Fundamentals of Information Systems, Second Edition 13 Networks and Distributed Processing Computer network - communications media, devices, and software needed to connect two or more computer systems. Centralized processing - processing occurs in a single location or facility. Decentralized processing - processing devices are placed at various locations. Distributed processing - computers are placed at remote locations but are connected to each other via telecommunications devices.

14 Fundamentals of Information Systems, Second Edition 14 Terminal-to-Host Connection Host computer has the data and the processing power Dumb terminal contacts host computer for jobs

15 Fundamentals of Information Systems, Second Edition 15 File Server Connection The application and database reside in host computer. Files transferred as a whole and processed by the user

16 Fundamentals of Information Systems, Second Edition 16 Client/Server Connection Servers have special functionalities (database server, program execution, etc.) Clients request services from servers Clients process service results

17 Fundamentals of Information Systems, Second Edition 17 Network Types Local area network (LAN) –Same geographic area –Wired into office buildings (unshielded twisted-pair) Wide area network (WAN) –Microwave and satellite transmission –Long-distance calls International network –Transborder data flow –International laws

18 Fundamentals of Information Systems, Second Edition 18 A Typical LAN

19 Fundamentals of Information Systems, Second Edition 19 A Wide Area Network

20 Fundamentals of Information Systems, Second Edition 20 Connecting Computing Devices Using a Home Network

21 Fundamentals of Information Systems, Second Edition 21 Communications Software and Protocols Communications software - provides a number of important functions in a network Network operating system - controls the computer systems and devices on a network and allows them to communicate with each other Network management software - a manager can monitor the use of individual computers and shared hardware Communications protocol - rules and standards that make communications possible

22 Fundamentals of Information Systems, Second Edition 22 Common Communications Protocols ProtocolDescription Open Systems Interconnection (OSI) Divides data communication into seven layers for maintenance Transport control protocol/Internet Protocol (TCP/IP) Primary communication protocol of the Internet EthernetUsed in LANs Asynchronous transfer mode (ATM) Organizes data into 53-byte cells for fast transmission aSupports wireless ATM devices BluetoothWireless communication for cell phones, handheld computers b (Wi-fi)

23 Fundamentals of Information Systems, Second Edition 23 Use and Functioning of the Internet

24 Fundamentals of Information Systems, Second Edition 24 Routing Messages Over the Internet

25 Fundamentals of Information Systems, Second Edition 25 How the Internet Works Internet Protocol (IP): Set of rules to pass packets from one computer to another Transport Control Protocol (TCP): Set of rules to establish and break connections Internet Protocol Address: Unique address for each computer on the Internet Static vs. dynamic

26 Fundamentals of Information Systems, Second Edition 26 U.S. Top-Level Domain Affiliations

27 Fundamentals of Information Systems, Second Edition 27 Three Ways to Access the Internet

28 Fundamentals of Information Systems, Second Edition 28 Internet Service Providers Organizations that provide access to the Internet Choose based on price, reliability, other features ( address) Examples: Superonline, E-kolay

29 Fundamentals of Information Systems, Second Edition 29 Internet and Telecommunications Services

30 Fundamentals of Information Systems, Second Edition 30 Summary of Internet Services (1) Instant messaging Telnet/SSH FTP Chat rooms Internet phone Internet video conferencing

31 Fundamentals of Information Systems, Second Edition 31 Summary of Internet Services (2) Shop on the Web: Auctions: Distance learning Music, radio on the Internet

32 Fundamentals of Information Systems, Second Edition 32 Common Abbreviations Used in Personal

33 Fundamentals of Information Systems, Second Edition 33 Two Approaches to Electronic Data Interchange

34 Fundamentals of Information Systems, Second Edition 34 Public Network and Specialized Services

35 Fundamentals of Information Systems, Second Edition 35 The World Wide Web

36 Fundamentals of Information Systems, Second Edition 36 The World Wide Web An Internet service comprising tens of thousands of independently owned computers that work together as one. –Home page: Cover page with text and graphics –Hypertext markup language (HTML): Standard language to describe Web pages

37 Fundamentals of Information Systems, Second Edition 37 Several Interesting Web Sites

38 Fundamentals of Information Systems, Second Edition 38 Sample HTML

39 Fundamentals of Information Systems, Second Edition 39 Search Engine

40 Fundamentals of Information Systems, Second Edition 40 Intranets and Extranets

41 Fundamentals of Information Systems, Second Edition 41 Intranets and Extranets Intranet – an internal corporate network built using Internet and WWW standards and products Extranet - a network that links selected resources of the intranet of a company with its customers, suppliers, or other business partners Virtual private network - a secure connection between two points across the Internet Firewall - a device that sits between your internal network and the outside Internet

42 Fundamentals of Information Systems, Second Edition 42 Summary of Internet, Intranet, and Extranet Users

43 Fundamentals of Information Systems, Second Edition 43 Virtual Private Network

44 Fundamentals of Information Systems, Second Edition 44 Net Issues

45 Fundamentals of Information Systems, Second Edition 45 Privacy and Security Cookie: Text that is put on user computer to track Web site usage Cryptography: Converting a message into a secret code and then back into the message Encryption Digital Signature: Who sent the message, did the message change on the way?

46 Fundamentals of Information Systems, Second Edition 46 Cryptography

47 Fundamentals of Information Systems, Second Edition 47 Summary Networks - used to share hardware, programs, and databases across the organization. Internet - transmits data from one computer (called a host) to another. The Web - a collection of tens of thousands of independently owned computers that work together as one in an Internet service.


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