管理信息系統(tǒng) MIS課件：ch03 Networks and Telecommunications

1、Introduction to MIS1Copyright 1998-2002 by Jerry PostIntroduction to MISChapter 3Networks and TelecommunicationsIntroduction to MIS2NetworksTeamworkCommunicationSchedulingSharingInternetSuppliersCustomersBanksInternalExternalIntroduction to MIS3OutlineIntroductionvSharing DatavSharing HardwarevShari

2、ng SoftwareComponents of a NetworkvComputersvMediavConnection DevicesvSoftwareNetwork StructurevShared MediavSwitchedStandardsThe InternetvHow the Internet WorksvInternet 2vMobile CommerceGlobal TelecommunicationsvTechnical ProblemsvPolitical ComplicationsvCultural IssuesvCommentCases: Specialty Ret

3、ailAppendix: Creating Web PagesIntroduction to MIS4Sharing Data: TransactionsDatabase ManagementSystem and Web ServerInternetIntroduction to MIS5Team DocumentFile Server and DatabaseData and ToolsReport andCommentsSharing Data: Decisions & SearchesDecisions & searchesTeamwork & joint aut

4、horshipIntroduction to MIS6Sharing Data: E-mailInternet1. User creates e-mail message.2. Message transferred to account on server.3. Transferred via the Internet to the destination account.4. Message received when user checks e-mail.Introduction to MIS7Server ScalabilitySun 10000Sun 3800Sun Ultra 5C

5、ompaqIncreasing performance within a product family.Server farms distribute the workload. Add more computers for more power.Rack mount server farm.Introduction to MIS8Network Transmission MediaElectricityFiber opticsRadio wavesCoaxialExample:Cable TVShieldRadio or Micro WavesExample:Cellular phonesg

6、lass or plasticFiber Optic CableExample:Long distance phone linesantennaTwisted PairExample:Local phone linesreflective claddingIntroduction to MIS9Fiber OpticsFasterMore dataLess magnetic interferenceLong stretches without repeaters900 copper wires can be replaced by one fiber optic line (for telep

7、hone connections).Introduction to MIS10Frequency SpectrumELFVLFLFMFHFVHFUHFMicrowaveOptical1001K100K1M10M100M1G10GHertzNavy/submarinesTV: 220M - 500 MHzAM: 550K - 1650 KHzPublic Safety: 150M - 160 MHzPublic Safety: 460M - 500 MHzCellular phones: 800 MHzCordless phones (some): 900 MHzPers. Com. Sys (

8、PCS): 1.85 G - 2.2 GHz PCS ET: 2 GHzTV: 54M - 216 MHzFM: 88M - 108 MHz/images/speccht.jpg/osmhome/allochrt.pdfIntroduction to MIS11Transmission CapacityA thin fiber optic cable can carry as much data as 900 single copper wires, with minimal interference, and su

9、perior tensile strength.Introduction to MIS12The Importance of Bandwidth Text Image Video-10 sec Bytes 10,000 500,000 15,000,000 Bits 80,000 4,000,000 120,000,000 seconds Dial-up 50 kbps 1.6 80 2400 DSL 1.5 mbps 0.05 2.67 80 LAN 10 mbps 0.008 0.4 12 LAN 100 mbps 0.0008 0.04 1.2 Gigabit 1 gbps 0.0000

10、8 0.004 0.12 Introduction to MIS13Shared ConnectionsWith shared connections, machines have to take turns, and congestion can slow down all connections.With switched connections, each computer has the full bandwidth of the connection at all times. Performance depends on how fast the switch can handle

11、 connections.Introduction to MIS14Time DivisionABDCtimeACACAComputers A and B split their messages into packets and sharethe transmission medium by taking turns sending the data.Introduction to MIS15Frequency DivisionABDCfrequency3500 HzACComputers A and B split the frequency: A uses a higher spectr

12、um.By listening only to the assigned frequency, multiple transmissionscan occur at the same time.Introduction to MIS16Spread SpectrumABDCfrequencytimeSharing a medium by both frequency and time is one methodof spread spectrum transmission. It is efficient for many computersbecause the full bandwidth

13、 can be utilized over time and frequency.Introduction to MIS17WirelessCommunicationMicrowave transmissions are used to provide communications for cellular phones and laptop computers. As prices of phones, portable computers, and communication costs decrease, increasing numbers of workers are choosin

14、g wireless technologies.Introduction to MIS18Connecting NetworksThe need for standardsA changing environmentBackbone fiber opticHubSwitchHubRadio-based networkInternetRouters or SwitchesIntroduction to MIS19Shared-Media NetworkShared MediaTapIntroduction to MIS20Switched NetworkSwitchServersWorkstat

15、ions/PCsIntroduction to MIS21Enterprise NetworkBuilding 1Building 2SwitchServersWorkstations/PCsFiber opticInternet ISPFirewallSubsidiaryIntroduction to MIS22Client/Server NetworkClient serverPeer-to-peervOperating systemvMultitaskingServerServerClientsClientsWorkgroup PrinterWorkgroup PrinterIntrod

16、uction to MIS23TCP/IP Reference ModelMessageHeader 3Trailer 3MessageHeader 3Trailer 3MessageHeader 3Trailer 3MessageHeader 2Trailer 2Header 3Trailer 3MessageHeader 3Trailer 3MessageHeader 2Trailer 2Header 1Trailer 14. Application3. Transport (TCP)2. Internet (IP)1. PhysicalIntroduction to MIS24TCP/I

17、P ReferenceApplicationvMail, Web, FTPvAuthentication, compression, user servicesTransportvPacketize data and handle lost packetsvEstablish connections through numbered portsInternet Protocol (IP)vRoute packets to destinationvRequires unique host addresses: IPv4=32-bit; IPv6=128-bitvRequires standard

18、s and cooperationSubnetvPhysical connectionsvTransfers bits with some form of error correctionIntroduction to MIS25ISO-OSI Reference ModelApplicationPresentationSessionTransportNetworkData LinkPhysicalLayer 7Layer 6Layer 5Layer 4Layer 3Layer 2Layer 1ApplicationPresentationSessionTransportNetworkData

19、 LinkPhysicalPhysical MediaOriginal DataTranslateSign on and resourcesData PacketRAdd routing dataRACAddresses &Error CheckRACRACIntroduction to MIS26The InternetIntroduction to the InternetNo controlServicesvMailvTelnetvFTPvWWWWEB searchingvAltaVistavHotBotvLycosvWebCrawlervYahooIntroduction to

20、 MIS27How the Internet WorksIndividualInternetserviceprovider (ISP)PhonecompanyNetworkserviceprovider (NSP)BackbonenetworkPhonecompanyCompanyWeb siteDial-up: 33.3 - 56 KbpsISDN: 128 KbpsDSL: 256 Kbps - 6 MbpsCable: 1 to 10 MbpsCablecompanyT1: 1.544 MbpsT3: 44.736 MbpsOC3: 155.52 MbpsOC12: 622 MbpsIn

21、troduction to MIS28Internet ConnectionsBackbone providersvAT&TvGTEvWorldcom/MCIvSprintvQwestNetwork service providersv1998: 39vAGISvAT&TvCable & WirelessvIBMvMCI/WorldcomvQwestvSprintvUUNetPhone companiesvRegional Bell operating companies (RBOCs) (6)vCompetitive local exchange carriers (

22、CLECs) (new)Cable companiesvAT&TvCablevisionvRegional.SatellitevDirect SatellitevStarbandInternet service providersvAmerica OnlinevMicrosoft NetworkvEarthlinkIntroduction to MIS29M-CommerceInternet access everywhereCell phonesPDAsLaptopsGreat potentialLimited usabilityBetter than voice?Introduct

23、ion to MIS30Cell Phones and Wireless CommunicationWireless cells work by handing off the wireless connection to the next tower as the caller moves.Connections to multiple towers at one time enables the system to triangulate to get a fairly precise location of the cellular device-even when it is not

24、in a call.Location knowledge will make it possible (although perhaps not desirable) to offer new business opportunities as people move into range.Introduction to MIS31Global TelecommunicationsTechnical problemsvMultiple standardsvLanguagevDeveloping nationsvTime zonesvLimits to space & wavesPoli

25、tical complicationsvTransborder data flowsvTaxesvPrivacyvAccessibilityCultural issuesvWhat is an object?vManagement & controlIntroduction to MIS32Cases: Specialty RetailIntroduction to MIS33Cases: Ben & JerrysIntroduction to MIS34Appendix: Creating Web PagesDetermine the content.Define a sty

26、le.Create each page.vTextvGraphicsLink the pages.Test your work.Transfer pages to a Web site.Introduction to MIS35Appendix: Style Sheets BODY margin-left: 5px;font: 10pt Times New Roman, Times, serif;color: black;text-align: left;background-color: #e0ffff; P margin-left: 0px;font: 10pt Times New Rom

27、an, Times, serif;color: black;background: transparent; H1 margin-left: 0px;font: 16pt Times New Roman, Times, serif;color: black;font-weight: bold;background: transparent;Page 3Page 2Page1Style SheetBody P Introduction to MIS36Appendix: Sample HTMLSample HTML PageSection OneThis is a sample paragrap

28、h on a sample page.Introduction to MIS37Appendix: Publishing FilesYour computerWeb serverInternet or intranetInitialpagesAccessibleWebpagesTransfer methods:Microsoft Front Page extensionsFTP: file transfer protocolIntroduction to MIS38Web Development HintsStart with a tool like Microsoft Word (or Fr

29、ont Page, etc.).Get a good graphics packageKeep page size smallv30,000 - 50,000 bytes typically takes 8 - 15 secondsFirst develop the pages on your own computer.vTest all links.vTransfer later.Use style sheets.vConsistency.vEase of change.Study design elements and art.vFormal training/art classes.vS

30、tudy other sites.vWatch for and create trends.Introduction to MIS39Sharing Data: E-mailInternet1. 用戶編寫郵件2. 郵件被發(fā)送到服務(wù)器的郵箱帳號(hào)中3. 通過Internet郵件被傳送到接收人的郵箱帳號(hào)中。4. 當(dāng)收件人查信時(shí)，就能收到.郵件Introduction to MIS40Sharing Data: Calendars 8:00管理會(huì)議 8:30(空閑) 9:00員工會(huì) 9:30員工會(huì)10:00新安排會(huì)Introduction to MIS41Hardware Sharing打印機(jī)存儲(chǔ)器C

31、PUFiles are transferred from workstations to the server.Software automatically copies files to tapes.LAN administrator can restore files if needed.集團(tuán)或外部計(jì)算機(jī)接服務(wù)器共享打印機(jī)工作站磁帶機(jī)(備份)Introduction to MIS42VoiceComputerSent as packets: 1 2 3 4 5Sent as packets: A B C D EChicagoNew YorkDallasAtlantaE4CB2A15D3Pa

32、cket-Switched NetworksData, Voice, VideovAll converted to packetsvPacket has data, destination, and source addressvSwitched servicesvPackets routed as neededvReassembled at destinationIntroduction to MIS43Network ComponentsComputersvServersvWork stationsMediavCablesvFiber opticvRadiovInfraredConnect

33、ion devicesLAN cardLAN cardLAN cardLAN cardShared PrinterServerPersonal ComputerPersonal ComputerRouter or SwitchInternetFirewallIntroduction to MIS44Server ScalabilitySun 10000Sun 3800Sun Ultra 5Compaq在同一產(chǎn)品系列中，不斷提升性能。服務(wù)器群分配負(fù)荷。計(jì)算機(jī)越多，能力就越大。柜架安裝式服務(wù)器群.Introduction to MIS45Frequency SpectrumELFVLFLFMFHF

34、VHFUHFMicrowaveOptical1001K100K1M10M100M1G10G赫茲海軍/潛艇電視: 220M - 500 MHzAM無線電: 550K - 1650 KHz公共安全: 150M - 160 MHz公共安全: 460M - 500 MHz蜂窩式電話: 800 MHz無繩電話: 900 MHz個(gè)人通信系統(tǒng): 1.85 G - 2.2 GHz 擴(kuò)展式個(gè)人通信系統(tǒng): 2 GHz電視: 54M - 216 MHzFM無線電: 88M - 108 MHz/images/speccht.jpg/osmh

35、ome/allochrt.pdfIntroduction to MIS46Transmission CapacityA thin fiber optic cable can carry as much data as 900 single copper wires, with minimal interference, and superior tensile strength.Introduction to MIS47The Importance of BandwidthIntroduction to MIS48Shared Connections共享網(wǎng)絡(luò)方式, 計(jì)算機(jī)需要排隊(duì)等待，堵塞會(huì)讓

36、整個(gè)網(wǎng)路慢下來交換網(wǎng)絡(luò)方式。每臺(tái)計(jì)算機(jī)在任何時(shí)間都可以占有全帶寬。此時(shí)性能取決于交換器處理的聯(lián)接的速度。Introduction to MIS49Time DivisionABDCtimeACACAComputers A and B split their messages into packets and sharethe transmission medium by taking turns sending the data.Introduction to MIS50Frequency DivisionABDCfrequency3500 HzACComputers A and B spli

37、t the frequency: A uses a higher spectrum.By listening only to the assigned frequency, multiple transmissionscan occur at the same time.Introduction to MIS51Spread SpectrumABDCfrequencytimeSharing a medium by both frequency and time is one methodof spread spectrum transmission. It is efficient for many computersbecause the full bandwidth can be utilized over time