Information Systems in BusinessChap006docresWord文件下载.docx

Information Systems in BusinessChap006docresWord文件下载.docx

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1.Understandtheconceptofanetwork.

2.ApplyMetcalfe’slawinunderstandingthevalueofanetwork.

3.Identifyseveralmajordevelopmentsandtrendsintheindustries,technologies,andbusinessapplicationsoftelecommunicationsandInternettechnologies.

4.ProvideexamplesofthebusinessvalueofInternet,intranet,andextranetapplications.

5.Identifythebasiccomponents,functions,andtypesoftelecommunicationsnetworksusedinbusiness.

6.Explainthefunctionsofmajorcomponentsoftelecommunicationsnetworkhardware,software,media,andservices.

7.Explaintheconceptofclient/servernetworking.

8.Understandthetwoformsofpeer-to-peernetworking.

9.Explainthedifferencebetweendigitalandanalogsignals.

10.Identifythevarioustransmissionmediaandtopologiesusedintelecommunicationsnetworks.

11.Understandthefundamentalsofwirelessnetworktechnologies.

12.ExplaintheconceptsbehindTCP/IP.

13.UnderstandthesevenlayersoftheOSInetworkmodel.

SUMMARY

•TelecommunicationsTrends.OrganizationsarebecomingnetworkedenterprisesthatusetheInternet,intranets,andothertelecommunicationsnetworkstosupportbusinessoperationsandcollaborationwithintheenterpriseandwiththeircustomers,suppliers,andotherbusinesspartners.Telecommunicationshasenteredaderegulatedandfiercelycompetitiveenvironmentwithmanyvendors,carriers,andservices.Telecommunicationstechnologyismovingtowardopen,internetworkeddigitalnetworksforvoice,data,video,andmultimedia.AmajortrendisthepervasiveuseoftheInternetanditstechnologiestobuildinterconnectedenterpriseandglobalnetworks,likeintranetsandextranets,tosupportenterprisecollaboration,e-commerce,andothere-businessapplications.

•TheInternetRevolution.TheexplosivegrowthoftheInternetandtheuseofitsenablingtechnologieshaverevolutionizedcomputingandtelecommunications.TheInternethasbecomethekeyplatformforarapidlyexpandinglistofinformationandentertainmentservicesandbusinessapplications,includingenterprisecollaboration,electroniccommerce,andothere-businesssystems.OpensystemswithunrestrictedconnectivityusingInternettechnologiesaretheprimarytelecommunicationstechnologydriversine-businesssystems.TheirprimarygoalistopromoteeasyandsecureaccessbybusinessprofessionalsandconsumerstotheresourcesoftheInternet,enterpriseintranets,andinterorganizationalextranets.

•TheBusinessValueoftheInternet.CompaniesarederivingstrategicbusinessvaluefromtheInternet,whichenablesthemtodisseminateinformationglobally,communicateandtradeinteractivelywithcustomizedinformationandservicesforindividualcustomers,andfostercollaborationofpeopleandintegrationofbusinessprocesseswithintheenterpriseandwithbusinesspartners.ThesecapabilitiesallowthemtogeneratecostsavingsfromusingInternettechnologies,revenueincreasesfromelectroniccommerce,andbettercustomerserviceandrelationshipsthroughbettersupplychainmanagementandcustomerrelationshipmanagement.

•TheRoleofIntranets.Businessesareinstallingandextendingintranetsthroughouttheirorganizationsto

（1）improvecommunicationsandcollaborationamongindividualsandteamswithintheenterprise;

（2）publishandsharevaluablebusinessinformationeasily,inexpensively,andeffectivelyviaenterpriseinformationportalsandintranetWebsitesandotherintranetservices;

and（3）developanddeploycriticalapplicationstosupportbusinessoperationsanddecisionmaking.

•TheRoleofExtranets.Theprimaryroleofextranetsistolinktheintranetresourcesofacompanytotheintranetsofitscustomers,suppliers,andotherbusinesspartners.Extranetscanalsoprovideaccesstooperationalcompanydatabasesandlegacysystemstobusinesspartners.Thus,extranetsprovidesignificantbusinessvaluebyfacilitatingandstrengtheningthebusinessrelationshipsofacompanywithcustomersandsuppliers,improvingcollaborationwithitsbusinesspartners,andenablingthedevelopmentofnewkindsofWeb-basedservicesforitscustomers,suppliers,andothers.

•TelecommunicationsNetworks.Themajorgenericcomponentsofanytelecommunicationsnetworkare

（1）terminals,

（2）telecommunicationsprocessors,（3）communicationschannels,（4）computers,and（5）telecommunicationssoftware.Thereareseveralbasictypesoftelecommunicationsnetworks,includingwideareanetworks（WANs）andlocalareanetworks（LANs）.MostWANsandLANsareinterconnectedusingclient/server,networkcomputing,peer-to-peer,andInternetnetworkingtechnologies.

•NetworkAlternatives.KeytelecommunicationsnetworkalternativesandcomponentsaresummarizedinFigure6.11fortelecommunicationsmedia,processors,software,channels,andnetworkarchitectures.Abasicunderstandingofthesemajoralternativeswillhelpbusinessendusersparticipateeffectivelyindecisionsinvolvingtelecommunicationsissues.Telecommunicationsprocessorsincludemodems,multiplexers,internetworkprocessors,andvariousdevicestohelpinterconnectandenhancethecapacityandefficiencyoftelecommunicationschannels.Telecommunicationsnetworksusesuchmediaastwisted-pairwire,coaxialcables,fiber-opticcables,terrestrialmicrowave,communicationssatellites,cellularandPCSsystems,wirelessLANs,andotherwirelesstechnologies.

•Telecommunicationssoftware,suchasnetworkoperatingsystemsandtelecommunicationsmonitors,controlsandmanagesthecommunicationsactivityinatelecommunicationsnetwork.

KEYTERMSANDCONCEPTS

1.Analog（235）:

Ananalogsignalisoneinwhichabasecarrier'

salternatingcurrentfrequencyismodifiedinsomeway,suchasbyamplifyingthestrengthofthesignalorvaryingthefrequency,inordertoaddinformationtothesignal.Broadcastandtelephonetransmissionhaveoriginallyusedanalogtechnology.

Ananalogsignalcanberepresentedasaseriesofsinewaves.Thetermoriginatedbecausethemodulationofthecarrierwaveisanalogoustothefluctuationsofthehumanvoiceorothersoundthatisbeingtransmitted.

2.Bandwidth（249）:

Bandwidthdescribesthetransmissionrateofatelecommunicationsmediaornetwork.

3.Bluetooth（239）:

Atelecommunicationsindustryspecificationforshortrangewirelesscommunications.

4.Client/ServerNetworks（232）:

Aclient/servernetworkisacomputingenvironmentwhereworkstations（clients）connecttoservers.

5.CoaxialCable（236）:

Asturdycopperoraluminumwirewrappedwithspacerstoinsulateandprotectit.Groupsofcoaxialcablesmaybebundledtogetherinabiggercableforeaseofinstallation.

6.Communicationssatellites（238）:

Earthsatellitesthatserveasrelaystationsforcommunicationssignals.

7.Digital（235）:

Digitaldescribeselectronictechnologythatgenerates,stores,andprocessesdataintermsoftwostates.Thesestatesaretypicallyrepresentedas"

0"

and"

1"

.

8.Extranets（223）:

Anetworkthatlinksselectedresourcesonanorganization'

snetworktoitscustomers,suppliers,orotherbusinesspartners,usinginternettechnologies.

9.Fiberoptics（236）:

Fiberopticsareatelecommunicationsmediathatusescablesconsistingofverythinfilamentsofglassfiberstotransmitlaserlightsignals.

10.InternetServiceProviders（217）:

AnISPisacompanythatprovidesaccesstotheInternettoindividualsandorganizations.

11.InternetNetworkingTechnologies（214）:

Internetnetworkingtechnologiesconsistofhardware,software,andstandardizedprotocolsusedtocreatetelecommunicationsnetworks.

12.Inter-networkProcessors（242）:

Internetworkprocessorssuchasbridges,routers,hubs,orgatewaystoothernetworks.

13.Intranets（221）:

Intranetsaresecure,Internet-likenetworksforuseonlywithinanorganization.

14.Legacysystems（232）:

Legacysystemsrefertoanorganization'

soutdatedbusinessinformationsystems.

15.LocalAreaNetworks-LANs（229）:

ALANisacommunicationsnetworkthatconnectscomputers,terminals,andothercomputerizeddeviceswithinalimitedphysicalareasuchasanoffice,building,floor,manufacturingplant,orworksite.

16.Metcalfe’sLaw（210）:

Metcalfe'

sLawexpressesthevalueofanetworkasthesquareofthenumberofitsusers.

17.Middleware（214）:

Middlewareisageneraltermforanyprogramthatservesto"

gluetogether"

ormediatebetweentwoseparateprograms.

18.Modems（MOdulation-DEModulation）（241）:

Amodemisadevicethatconvertsthedigitalsignalsfrominput/outputdevicesintoanalogsignalsfortransmissionoverananaloguecarrieratthesendingnodeandconvertsanalogsignalsbackintodigitalsignalsatthereceivingnode.

19.Multiplexer（243）:

Anelectronicdevicethatallowsasinglecommunicationschanneltocarrysimultaneousdatatransmissionsfrommanyterminals.

20.Network（210）:

Aninterconnectedsystemorsystems.

21.NetworkArchitectures（245）

Anorganization'

stelecommunicationsenvironmentincludingcomputers,software,communicationsstandards,andtransmissionmedia.

a.OpenSystemsInterconnection-OSI（214）:

Aseven-layerOpenSystemsInterconnection（OSI）developedbytheInternationalStandardsOrganization（ISO）toserveasastandardmodelfornetworkarchitecturesinordertopromoteanopen,simple,flexible,andef