F新版CCNA培训教材ch05

5BasicSwitchandRouterConfigurationCERTIFICATIONOBJECTIVES5.01IOSIntroduction5.02IOSBasics5.03BasicSwitchConfiguration5.04BasicRouterConfiguration✓Two-MinuteDrillQ&ASelfTestCertPrs8/CCNACiscoCertifiedNetworkAssociateStudyGuide/Deal/222934-9/Chapter5BlindFolio5:1D:\omh\CertPrs8\934-9\ch05.vpMonday,August04,200311:24:05AMColorprofile:GenericCMYKprinterprofileCompositeDefaultscreenThischapterpresentsthebasicsofconfiguringthe1900and2950CatalystswitchesaswellasCiscorouters.Asyoucontinuethroughoutthisbook,youwillbuilduponthesefundamentalandimportantconceptsforaccessing,configuring,andmanagingyourCiscodevices.IammakingtheassumptionthatyouhaveneverconfiguredaCiscodevicebeforeandthereforewillbeginwiththeverybasicsbyexplainingtheoperatingsystemthatthesedevicesuse,theadvantagesthatCisco’soperatingsystemprovides,andhowtousesomebasicoperatingsystemcommandstoconfigureyourCiscodevice.CERTIFICATIONOBJECTIVE5.01IOSIntroductionOneofthemainreasonsthatCiscoisnumberoneintheenterprisenetworkingmarketplaceistheirInternetworkOperatingSystem(IOS).TheIOSprovidesasimilarfunctiontoMicrosoftWindowsXPorLinux:itcontrolsandmanagesthehardwareitisrunningon.Basically,theIOSprovidestheinterfacebetweenyouandthehardware,enablingyoutoexecutecommandstoconfigureandmanageyourCiscodevice.Originally,theIOSwasdevelopedforCiscorouters,butoverthelastfewyears,CiscohasbeenportingtheIOStoitsotherplatforms,includingtheCatalystswitches.CiscohasspentmanyyearstweakingandtuningtheIOS,aswellasaddingfeaturesasnewtechnologiesareintroducedtothemarketplace.AdvantagesoftheIOSinclude:■FeaturesTheIOSincludesawidearrayoffeaturesforprotocolsandfunctionsthatprovideconnectivity,scalability,reliability,andsecuritysolutionsfornetworksofanysize.■ConnectivityTheIOSsupportsavarietyofdatalinklayertechnologiesfortheLANandWANenvironments,includingcopperandfiberwiringaswellaswireless.■ScalabilityTheIOSsupportsbothfixedandmodularchassisplatforms,enablingyoutopurchasetheappropriatehardwareforyourneeds,yetstillallowingyoutoleveragethesameIOSCLItoreduceyourmanagementcosts.■ReliabilityToensurethatyourcriticalresourcesarealwaysreachable,CiscohasdevelopedmanyproductsandIOSfeaturestoprovidenetworkredundancy.■SecurityWiththeIOS,youcanstrictlycontrolaccesstoyournetworkandnetworkingdevicesinaccordancewithyourinternalsecuritypolicies.2Chapter5:BasicSwitchandRouterConfigurationCertPrs8/CCNACiscoCertifiedNetworkAssociateStudyGuide/Deal/222934-9/Chapter5D:\omh\CertPrs8\934-9\ch05.vpMonday,August04,200311:24:05AMColorprofile:GenericCMYKprinterprofileCompositeDefaultscreenBecauseofthesuccessoftheirIOSsoftware,Ciscohasgrownfromagarage-basedroutercompanytooneofthelargestcompaniesintheworldinalittleoveradecade.Mostenterprisenetworks,aswellasISPs,useCiscoproductsinoneformoranother.Actually,alargeportionoftheInternetbackboneiscomposedofCiscoproducts.WiththeIOScoupledwithafirst-classserviceandsupportteam,fewcompaniescancomparetoCiscowhenitcomestocustomersatisfaction.DeviceStartupThereareactuallymanywaysofaccessingaCiscodevice,includingthefollowing:console,auxiliary(onlycertainCiscorouters),telnet,webbrowser,andanSNMPmanagementstation.Aconsoleinterfaceprovidesserialconnectionaccesstoarouter—withconsoleaccess,youcanentercommandsinatext-basedmode.InordertoaccessyourCiscodevicefromaremotestation,however,youfirstneedtocreateabasicconfiguration,includingIPaddressing.Therefore,toperformyourinitialconfigurations,youneedaccesstotheconsoleportofyourCiscodevice.BeforeyoucanactuallybeginconfiguringyourCiscodevice,youfirsthavetoconnectittoyournetworkandsetupaterminalconnectiontoitsconsoleinterface,asdescribedintheChapter4.HerearethethreestepsyourCiscodevicegoesthroughwhenbootingup:1.Performhardwaretests.2.LocateandloadtheIOS.3.Locateandexecutethedevice’sconfigurationfile.OnceyoupoweronyourCiscodevice,hardwaretestsareperformedtoensurethatitisoperatingcorrectly.Thesetests,power-onselftests(POST),arediscussedinChapter4.Afterthesetestshavecompleted,theCiscodevicefindsandlocatestheIOSandthenproceedstoloadit.OncetheIOSisloaded,theIOSthensearchesforthedevice’sconfigurationandexecutesit.Withsteps2and3,therearetypicallyfallbackmeasuresthattheCiscodevicegoesthroughifitcannotfindanIOSorlocateaconfigurationfile.Asyouwillseeinthischapter,andasyouworkwithCiscodevicesinaproductionenvironment,eachCiscoproductisuniqueandmayhaveitsownmethodsforfindingandloadingitsIOSandconfigurationfile.Asanexample,aCatalyst1900switch,IOSIntroduction3CertPrs8/CCNACiscoCertifiedNetworkAssociateStudyGuide/Deal/222934-9/Chapter5IOSstandsforInternetworkOperatingSystem.Itsadvantagesincludefeatures,connectivity,scalability,reliability,andsecurity.D:\omh\CertPrs8\934-9\ch05.vpMonday,August04,200311:24:05AMColorprofile:GenericCMYKprinterprofileCompositeDefaultscreendirectfromCisco,comeswithadefaultconfigurationalreadyonit.Thisconfigurationisenoughtoallowtheswitchtoperformbasicswitchingfunctionsrightoutofthebox.ACiscorouter,bycontrast,requiressomebasicconfigurationinordertoroutetrafficbetweeninterfaces.AccessingtheCommand-LineInterface(CLI)HowyouaccesstheIOSCLI