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Chapter 10 Data Communications MANAGEMENT INFORMATION SYSTEMS 8/E

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Presentation on theme: "Chapter 10 Data Communications MANAGEMENT INFORMATION SYSTEMS 8/E"— Presentation transcript:

1 Chapter 10 Data Communications MANAGEMENT INFORMATION SYSTEMS 8/E
Raymond McLeod, Jr. and George Schell Chapter 10 Data Communications 10-1 Copyright 2001 Prentice-Hall, Inc. 1

2 Communication Basics Computer communications is at three levels
Application level Computer level Communication channel Protocol Set of rules for communications OSI Standard 10-2 2

3 OSI Reference Model Layer Name Purpose
7 Application Layer Application-to-application communication 6 Presentation Layer Manage data representation conversions 5 Session Layer Establish and maintain communication channel 4 Transport Layer Guarantee end-to-end integrity of transmission 3 Network Layer Route data between network addresses 2 Data Link Layer Move data from one network address to another 1 Physical Layer Put data onto and off of the network media 10-3

4 ISO Website 10-4

5 Protocols for Computer Communication
Early computers Terminals Sneaker net System Network Architecture (SNA) Established by IBM in 1974 Proprietary Token-Ring Host computer controlled peer-to-peer 10-5

6 Protocols for Computer Communication
Ethernet Xerox working with Intel and Digital Equipment Corporation developed this protocol Non-proprietary Defined by IEEE Works on a single transmission line No token is passed 10-6

7 Packets Piece of the total data to be communicated, combined with the address of the destination computer for the data and other control information. Transmission Control Protocol/Internet Protocol (TCP/IP) is one of the more important packet switching protocols 10-7 4

8 Network Addresses Address Internet Service Providers (ISPs)
Four-part set of numbers Each from 0 to 255 Internet Service Providers (ISPs) User connects through common carrier Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) Protocols for users at home 10-8

9 Protocols for Public Phone Systems
X.25 analog older protocol Integrated Services Digital Network (ISDN) Digital Can carry voice, data, and video 10-9

10 Protocols for Public Phone Systems (cont.)
Frame Relays Move to fiber optics Asynchronous Transfer Mode (ATM) Smaller packet size Faster transmission speeds 10-10

11 Data Communications Links the General Systems Model Elements
Standards Information processor Environment Management Input Transformation Output 10-11

12 Networks Each device must be connected to the communications medium via a network interface card (NIC) 10-12

13 Types of Networks LAN (local area network)
Limited area but could include 100 or so micros Facilitates office automation MAN (metropolitan area networks) spans one city/metropolitan area WAN (wide area network) Covers a large geographic area Includes a wide variety of circuits Usually includes host computers 10-13 7

14 A Local Area Network Users Workstation 1 Manager 1 Letter Quality
Printer Workstation 2 Network Server Secretary 1 Users Workstation 3 Plotter Secretary 2 Hard Disk Workstation 4 Manager 2 A Local Area Network 10-14 29

15 Common LAN Topologies Star

16 Common LAN Topologies Ring

17 Common LAN Topologies Bus

18 Wide Area Network Earth Satellite Local Earth loop station station
User’s modem IXC circuit Local loop Earth station (interexchange channel) Earth station Telephone company central office Microwave tower IXC circuit (interexchange channel) Microwave tower Local loop Telephone company central office User’s modem Telephone company central office Telephone company central office 10-18 13

19 Types of Networks (cont.)
Internet Collection of networks Public Intranet Uses Internet network protocols Limits accessibility Firewall Extranet For trusted business partners and customers 10-19 7

20 Control of Data Communications Networks
Centralized Point-of-sale terminals Data collection terminals Distributed processing Receiving computer runs programs that use data Client/server processing Mixes centralized and decentralized processing strategies 10-20

21 A Network of Terminals Legend: Computer Terminal 10-21 22

22 A Distributed Processing Network
Legend: Central Distributed Computer Computer 10-22 23

23 Communications Hardware
Modem Converts digital to analog and vice versa Bits per second determines transmission speed Local loop Hub Receives a data packet from a computer at one end of one spoke of the star topography and copies its contents to all other computers Manageable hubs 10-23 11

24 Data Communications with a Modem
Computer Computer Modem Channel Modem A modem is always required between a telephone and a digital computer 10-24 5

25 Communications Hardware (cont.)
Router Device that connects many LANs More sophisticated than a bridge Process header information of a packet Switch Filters data not intended for a computer on a particular network 10-25 11

26 Communications Connections
Private Lines Circuit that is always open to communications traffic Also called leased line or dedicated line Two types T-1 - Maximum speed just over 1.5 Mbps T-3 - Maximum speed 43 Mbps Collections of 64 Kbps connections 10-26

27 Communications Connections (cont.)
Virtual Private Networks (VPNs) Tunneling software makes Internet connections more secure Privacy through authentication More cost effective than private lines 10-27

28 Network Management Digital nervous systems of an organization
Network planning Anticipates firm’s network needs Monitor’s performance Network Control Determines faults Errors in data communication Alerts to potential faults 10-28

29 Network Management (cont.)
Network manager Planning, implementing, operating, and controlling a firm’s data communications network(s) Staff Network analysts (a type of systems analyst) Software analysts Data Communication Technicians (specialize in hardware) LAN managers 10-29

30 Wireless Networks Cellular networks Wireless LANs
Hand held telephones Primarily for voice Wireless LANs Extensions of regular LANs Wide-area wireless networks Nationwide Highlights in MIS 10-30

31 Wireless Networks (cont.)
Paging networks Receive only capability Personal Communications Network (PCN) is the networking infrastructure for wireless. It is not yet in place! Highlights in MIS 10-31

32 A Network with Mobility Capability
MU MU MU MU MU MU Fixed host MSS MSS Fixed network Fixed host Fixed host MSS MSS Fixed host MU MU MSS = mobile support station MU = mobile units MU MU MU MU Highlights in MIS 10-32

33 Summary Data communications enable computers to share information and applications Networks LANs MANs WANs Communication standards 10-33

34 Summary [cont.] Basic Hardware Planned growth Hubs Routers Bridges
Switches Planned growth 10-34

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