MANAGEMENT INFORMATION SYSTEMS 8/E

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Tobias Franklin
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2 Objectives Understand data communication basics. Know the data transmission speed for communication between computers. Be familiar with local area networks, metropolitan area networks, wide area networks, and the Internet of networks. Understand the two main local area network protocols-- Token-Ring and Ethernet. Understand the data communication services provided by public telephone systems, also known as common carriers. Be familiar with communications hardware that supports networking.

Understand the two main local area network protocols-- Token-Ring and Ethernet.

3 Communication Basics Computer communications is at three levels Application level Computer level Communication channel Protocol Set of rules for communications OSI Standard 10-3

4 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 10-4

Transport Layer Guarantee end-to-end integrity of transmission 3 Network Layer Route data between network addresses

5 ISO Website 10-5

6 Protocols for Computer Early computers Terminals Sneaker net Communication System Network Architecture (SNA) Established by IBM in 1974 Proprietary Token-Ring Host computer controlled peer-to-peer 10-6

7 Ethernet Protocols for Computer Communication 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 10-7

developed this protocol Non-proprietary Defined by

8 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 10-8

9 Network Addresses Address 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 10-9

through common carrier Serial Line Internet Protocol (SLIP)

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

11 Protocols for Public Phone Frame Relays Systems (cont( cont.) Move to fiber optics Asynchronous Transfer Mode (ATM) Smaller packet size Faster transmission speeds 10-11

12 Data Communications Links the General Systems Model Elements Standards Management Information processor Environment Input Transformation Output 10-12

13 Networks Each device must be connected to the communications medium via a network interface card (NIC) 10-13

14 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 10-14

spans one city/metropolitan area WAN (wide area network) Covers a large

15 Workstation 1 Manager 1 Workstation 2 Letter Quality Printer Users Secretary 1 Network Server Workstation 3 Plotter Secretary 2 Workstation 4 Hard Disk Manager 2 A Local Area Network 10-15

16 Common LAN Topologies Star 10-16

17 Common LAN Topologies Ring 10-17

18 Common LAN Topologies Bus 10-18

19 Wide Area Network Satellite User s modem Local loop Earth station IXC circuit (interexchange channel) Telephone company central office Microwave tower IXC circuit (interexchange channel) Microwave tower Earth station Local loop Telephone company central office Telephone company central office Telephone company central office User s modem 10-19

(interexchange channel) Microwave tower Earth station Local loop Telephone company

20 Internet Types of Networks (cont( cont.) Collection of networks Public Intranet Uses Internet network protocols Limits accessibility Firewall Extranet For trusted business partners and customers 10-20

21 Control of Data Communications Centralized Networks 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 10-21

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

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

24 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 10-24

25 Data Communications with a Modem Computer Modem Channel Modem Computer A modem is always required between a telephone and a digital computer 10-25

26 Communications Hardware (cont( 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 10-26

27 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 10-27

28 Communications Connections (cont.) Virtual Private Networks (VPNs( VPNs) Tunneling software makes Internet connections more secure Privacy through authentication More cost effective than private lines 10-28

29 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 10-29

30 Network Management (cont( 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 10-30

31 Wireless Networks Cellular networks Hand held telephones Primarily for voice Wireless LANs Extensions of regular LANs Wide-area wireless networks Nationwide Highlights in MIS 10-31

32 Wireless Networks (cont( 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 10-32

33 A Network with Mobility Capability MU MU MU MU MU MU MSS Fixed host MSS Fixed host Fixed network Fixed host MSS Fixed host MSS MU MU Highlights in MIS MSS = mobile support station MU = mobile units MU MU MU MU 10-33

34 Summary Data communications enable computers to share information and applications Networks LANs MANs WANs Communication standards 10-34

35 Summary [cont.] Basic Hardware Hubs Routers Bridges Switches Planned growth 10-35

36 Case Study 1. A LAN is a group of computers and other devices connected together by a common medium-- typically in the same building. A)TRUE B)FALSE 2. A WAN includes a component of a public phone system or other common carrier. A)TRUE B)FALSE

Local-Area Network -LAN

Local-Area Network -LAN Computer Networks A group of two or more computer systems linked together. There are many [types] of computer networks: Peer To Peer (workgroups) The computers are connected by a network, however, there