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Alter – Information Systems © 2002 Prentice Hall 1 Networks and Telecommunications.

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Presentation on theme: "Alter – Information Systems © 2002 Prentice Hall 1 Networks and Telecommunications."— Presentation transcript:

1 Alter – Information Systems © 2002 Prentice Hall 1 Networks and Telecommunications

2 Alter – Information Systems © 2002 Prentice Hall 2 Opening Case: FedEx Tracks each package through each step from shipper to recipient Expanded into being a fully integrated corporate partner that picks up, transports, warehouses, and delivers a customers finished goods E-business tools

3 Alter – Information Systems © 2002 Prentice Hall 3 Applying Telecommunications in Business TELECOMMUNICATIONS – the transmission of data between devices in different locations

4 Alter – Information Systems © 2002 Prentice Hall 4 Vital Role of Telecommunications in E-Business Telecommunications essential to: E-retailers E-marketplaces Internet content providers Internet service providers (ISPs) Application service providers (ASPs) Telephone and cable companies Telecommunication equipment manufacturers Internet and telecommunications software firms

5 Alter – Information Systems © 2002 Prentice Hall 5 Convergence of Computing and Communications Reliance of telecommunications on computers Role of telecommunications in computing New wired and wireless transmission New combinations of data and computing

6 Alter – Information Systems © 2002 Prentice Hall 6 Figure 10.1

7 Alter – Information Systems © 2002 Prentice Hall 7 Figure 10.2

8 Alter – Information Systems © 2002 Prentice Hall 8 Types of Networks

9 Alter – Information Systems © 2002 Prentice Hall 9 A Typical Home Network Figure 10.3

10 Alter – Information Systems © 2002 Prentice Hall 10 A Local Area Network (LAN) in a Business LANs connect PCs and other equipment within a local area Benefits: Sharing equipment Sharing personal files Sending messages Sharing databases Administering software Usually wired, but may also be wireless

11 Alter – Information Systems © 2002 Prentice Hall 11 Figure 10.4

12 Alter – Information Systems © 2002 Prentice Hall 12 A Telephone Network: Figure 10.6

13 Alter – Information Systems © 2002 Prentice Hall 13 The Internet (From a Users Viewpoint): Figure 10.7

14 Alter – Information Systems © 2002 Prentice Hall 14 A Wide Area Network (WAN) WANs are networks that span a wide geographical area Many uses, e.g., Form the communication backbone for large distributed organizations Focus on particular transaction processing application(s) Transfer and consolidate corporate data, etc.

15 Alter – Information Systems © 2002 Prentice Hall 15 Figure 10.8

16 Alter – Information Systems © 2002 Prentice Hall 16 Functions and Components of Telecommunication Networks

17 Alter – Information Systems © 2002 Prentice Hall 17 Basic Terminology Network Network = a set of devices and communications channels nodes Devices are called nodes Connectivity Connectivity = the ability to transmit data between devices at different locations Switching Switching = the process of directing a signal from its source to its destination

18 Alter – Information Systems © 2002 Prentice Hall 18 Channel Channel = a path along which data are transmitted Wired or wireless Decoding Decoding = converting the data back into their original form upon arrival at its destination Network management Network management = the process of monitoring the networks operations, detecting and repairing faults, and balancing traffic

19 Alter – Information Systems © 2002 Prentice Hall 19 Figure 10.9

20 Alter – Information Systems © 2002 Prentice Hall 20 Generating and Receiving Data An ever increasing number of different types of devices can be connected to a network General purpose Special purpose Front-end processor – a specialized computer that handles network traffic for another computer Improves the efficiency of the overall system

21 Alter – Information Systems © 2002 Prentice Hall 21 Transmitting Analog versus Digital Data Data transmission requires that data be encoded as electrical or optical signals, and then decoded at destination Two important factors: Are the original data analog or digital? Are the data transmitted in analog or digital form?

22 Alter – Information Systems © 2002 Prentice Hall 22 Analog data, analog signal Original signal added to a carrier signal Used for voice communication Analog data, digital signal Data must be digitized The digitized data are only an approximation of the original The quality depends on the precision of the digitizing process

23 Alter – Information Systems © 2002 Prentice Hall 23 Digital data, analog signal modem Must use a modem at each end Superimposes a pattern of 0s and 1s on the carrier signal Digital data, digital signal Modems are no longer needed Digital subscriber line (DSL)

24 Alter – Information Systems © 2002 Prentice Hall 24 Significance of analog vs. digital transmission Digital technology improves the quality of the transmission Digital coding allows for error detection and correction Digital data can be readily manipulated High definition television (HDTV)

25 Alter – Information Systems © 2002 Prentice Hall 25 Directing Data From Source to Destination Dedicated line Dedicated line – a telephone line leased by a firm, and used exclusively by that firm Switch Switch – a special purpose computer that directs incoming messages along a path Private branch exchange (PBX) Private branch exchange (PBX) – a special-purpose computer that distributes calls within a customers site

26 Alter – Information Systems © 2002 Prentice Hall 26 Circuit Switching vs. Packet Switching CIRCUIT SWITCHING CIRCUIT SWITCHING: The method used in telephone networks Sets up a temporary circuit between the source and the destination Resources are reserved for the duration of the session (call)

27 Alter – Information Systems © 2002 Prentice Hall 27 PACKET SWITCHING PACKET SWITCHING: Appropriate when data are transmitted infrequently from a large number of nodes Used on the Internet The message is divided into packets containing control information No circuit is established Provides better sharing of resources Multiple users share the same resources

28 Alter – Information Systems © 2002 Prentice Hall 28 Figure 10.13

29 Alter – Information Systems © 2002 Prentice Hall 29 Transmitting Data Through Wire and Wireless Media Bandwidth – corresponds to the capacity of the transmission channel Mbps or Gbps A major limitation for the information superhighway

30 Alter – Information Systems © 2002 Prentice Hall 30 Wired Transmission TWISTED PAIR TWISTED PAIR Used for voice transmission and for low volume data transmission Slow COAXIAL CABLE COAXIAL CABLE Used in LANs and for data transmissions of less than 10 miles Faster and more versatile than twisted pair

31 Alter – Information Systems © 2002 Prentice Hall 31 FIBER OPTIC FIBER OPTIC Carries data in the form of light Extremely fast Very light Very difficult to tap into Very little data loss Costly

32 Alter – Information Systems © 2002 Prentice Hall 32 Wireless Transmission Figure 10.16

33 Alter – Information Systems © 2002 Prentice Hall 33 Telecommunications Standards De facto standards – established by the fact that a product dominates the market, e.g., Windows De jure standards – defined by industry groups or by the government Many de facto standards become de jure standards

34 Alter – Information Systems © 2002 Prentice Hall 34 OSI (open systems interface) model The OSI (open systems interface) model is a framework for defining telecommunications standards Covers all aspects of network operations and management Developed by the International Standards Organization (ISO) Each level in the model is implemented through protocols

35 Alter – Information Systems © 2002 Prentice Hall 35 Figure 10.18

36 Alter – Information Systems © 2002 Prentice Hall 36 TCP/IP (Transmission Control Protocol/ Internet Protocol) Used on the Internet Five layer model HTML and HTTP are examples of application layer standards Open vs. proprietary standards

37 Alter – Information Systems © 2002 Prentice Hall 37 More About Network Technology

38 Alter – Information Systems © 2002 Prentice Hall 38 More About LANs Main topologies: Star Star – all messages go through a central node that serves as a switch Ring Ring – the nodes are linked directly in a closed loop Bus Bus – each node is attached to a central channel called a bus

39 Alter – Information Systems © 2002 Prentice Hall 39 Token passing : One of the most common methods for internal communication Used in ring topologies Token – a bit pattern that circulates between the nodes To transmit data, a node appends it to the token

40 Alter – Information Systems © 2002 Prentice Hall 40 LANs use two types of transmission: Baseband Baseband – the entire capacity of the cable is used to transmit a single digitally encoded signal Ex.: Ethernet Broadband Broadband – the capacity of the cable is divided into separate frequencies to permit it to carry several signals at the same time

41 Alter – Information Systems © 2002 Prentice Hall 41 Interconnection devices – a combination of hardware and software: Routers Bridges Gateways

42 Alter – Information Systems © 2002 Prentice Hall 42 More About WANs Virtual private networks (VPNs) Virtual private networks (VPNs): A private network configured within a public network Can be built on top of the Internet Service offered by the telephone companies and ISPs

43 Alter – Information Systems © 2002 Prentice Hall 43 Value added networks (VANs): Value added networks (VANs): Public data networks that add value by transmitting data and by providing access to commercial databases and software Use packet switching Subscription based Often used in electronic data interchange (EDI) systems

44 Alter – Information Systems © 2002 Prentice Hall 44 Public switched data network technologies (PSDN) Public switched data network technologies (PSDN) Data flows through a public network managed by a telecommunications carrier Most common technologies: ISDN (integrated service digital network) X.25 Frame relay Asynchronous transfer mode (ATM)

45 Alter – Information Systems © 2002 Prentice Hall 45 Wireless Networking Wireless application protocol (WAP) - a standard technology framework for wireless Internet Allows for some of the Internet content to be accessed by mobile devices Bluetooth – a fast short-range wireless technology Wireless office

46 Alter – Information Systems © 2002 Prentice Hall 46 IP Telephony Voice over the Internet Limited by the packet switching technology currently used by the Internet

47 Alter – Information Systems © 2002 Prentice Hall 47 Telecommunications Policy Why should the government permit only some companies to sell products in a particular line of business? What should be the rationale for regulating telecommunications and setting prices? Who should be able to use specific public resources, such as radio frequencies? To what extent is universal access possible and to what extent should it be guaranteed?


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