OLeary2008CEComplete Chapter9 Communications and Networksppt课件

Chapter9 CommunicationsandNetworks 9 2 Competencies Page1of2 Discussconnectivity thewirelessrevolution andcommunicationsystemsDescribephysicalandwirelesscommunicationschannelsDiscussconnectiondevices includingmodems T1 DSL cablemodem satellite andcellularconnectionsDescribedatatransmissionfactors includingbandwidthsandprotocols Page246 9 3 Competencies Page2of2 Discussnetworksandkeynetworkterminologies Describedifferenttypesofnetworks includinglocalarea metropolitanarea andwideareanetworks Describenetworkarchitectures includingconfigurationsandstrategies DescribeorganizationalusesofInternettechnologies includingintranets extranets andfirewalls Page246 9 4 Introduction Cellphonesandotherwirelesstechnologiesareallowingustostayconnectedintoday sworldlikeneverbefore Increasedconnectivitypotentiallymeansincreasedproductivityespeciallyinthebusinessworld Youwilllearnmoreabouttheconceptofconnectivityandtheimpactofthewirelessrevolutioninthischapter Page247 9 5 Communications Theprocessofsharingdata programs andinformationbetweentwoormorecomputers Page248 9 6 CommunicationsToday Numerousapplicationsdependoncommunicationsystems E mail Instantmessaging IM Internettelephone andElectroniccommerceConnectivityusescomputernetworkstolinkpeopleandresourcesGoingwirelesshasbeenthemostdramaticchange Page248 9 7 CommunicationSystems FourbasicelementsSendingandreceivingdevicesCommunicationchannelConnectiondevicesDatatransmissionspecifications Page249 9 8 CommunicationChannels ChannelscarrydatafromonecomputertoanotherTwocategoriesofcommunicationchannelsPhysicalconnectionWirelessconnection Page250 9 9 PhysicalConnections Telephonelines Twistedpaircables CoaxialcableFiber opticcable Page250 Return 9 10 WirelessConnections InfraredBroadcastradioWi FI wirelessfidelity 802 11MicrowaveStationsBluetoothSatelliteGPS Page252 Microwavedish GPS Satellite 9 11 CommunicationChannelsSummary Page253 9 12 ConnectionDeviceSignals TypesofsignalsAnalogDigital Page253 9 13 ConnectionDeviceTypesandTransferSpeeds TypesofmodemsExternalInternalPCCardWireless Page253 TransferSpeeds 9 14 ConnectionService Dial UpservicesLeasedlines T1 T2 T3andT4Digitalsubscriberline DSL UsesexistingphonelinesOnetypewidelyusedisADSLCablemodemsUsesexistingTVcableProvidesspeedsasfastasDSLatalowercostSatellite airconnectionservicesSeventimesfasterthandial upSlowerthanDSL cablemodemCellularServicesAlternativeformobiledevicesandlaptopsCurrentserviceareaslimited Page254 9 15 TypicalUserConnectionCosts Speeds Page255 9 16 Bandwidth MeasurementofthecapacityofthechannelCategoriesVoicebandalsoknownaslowbandwidthMediumbandBroadbandUsedforhighcapacitytransmissionUsedbyDSL cable andsatellite Page255 9 17 Protocols SetofcommunicationrulesStandardforInternet TCP IP Transmissioncontrolprotocol Internetprotocol IdentificationReformatting Page256 9 18 Networks AcomputernetworkisacommunicationsystemConnectstwoormorecomputersAllowsinformationexchange Page257 9 19 ComputerNetworks CommonnetworktermsNodeClientServerHubNetworkinterfacecards NIC Networkoperatingsystem NOS DistributedprocessingHostcomputerNetworkadministrator Page257 ComputerNetworksConnectComputers 9 20 NetworkTypes LocalareanetworksHomenetworksWLANMetropolitanareanetworksWideareanetworks Page259 LAN 9 21 NetworkArchitecture ArchitecturedescribeshowanetworkisarrangedArrangementiscalledtopologyTypesofnetworktopologyStarBusRingHierarchical Page261 9 22 StarNetwork SmallercomputerslinkedtoacentralunitCentralunitiscalledthenetworkhubControlismaintainedbypolling Page251 Return 9 23 BusNetwork EachdevicehandlesitsowncommunicationcontrolThereisnohostcomputerHasacommonconnectingcablecalledabackbone Page264 Return 9 24 RingNetwork EachdeviceisconnectedtotwootherdevicesNocentralfileserverorcomputerUsefulinadecentralizedenvironment Page264 Return 9 25 HierarchicalNetwork SeveralcomputerslinkedtoacentralhostComputersarehoststoothercomputersUsefulincentralizedorganizations Page264 9 26 PrincipalNetworkConfigurations Page265 9 27 Strategies StrategyisawayofcoordinatingthesharingofinformationandresourcesCommonnetworkstrategiesTerminalClient serverPeer to peer Page255 9 28 OrganizationalInternets IntranetsPrivatenetworkwithinanorganizationProvidesinformationtoemployeesExtranetsPrivatenetworkthatconnectsorganizationsUsedtoallowsuppliersandothersaccessFirewallsSecuritysystemProtectsagainstexternalthreats Page268 9 29 CareersInIT NetworkAdministratorManageacompany sLANandWANnetworksMaintainhardwareandsoftwareDiagnoseandrepairproblemsCandidatesusuallyhaveabachelor sdegreeincomputerscienceandpracticalexperienceAnnualsalaryistypicallybetween 43 000and 68 000 Page270 9 30 ALooktotheFutureCarsthatMonitorandRespond Podcar PersonalizationonDemand PredictsandrespondsDesignedtolearnandadapttoanindividual sdrivingneedsandhabits Page271 9 31 DiscussionQuestions 1of2 Defineanddiscussconnectivity thewirelessrevolution andcommunications Identifyanddescribethevari