PCCPU、內(nèi)存、BOOTROM。路由器沒有鍵RAM/DRAM：內(nèi)存，用于存儲臨時的運算結(jié)果，如：路由表、ARP緩沖數(shù)據(jù)包、數(shù)據(jù)隊列、當(dāng)前配置。眾所周知，RAM丟失。FLASH容量較大時，就可以存放多個IOS版本。，ROM（InterfaceSystem是命令行界面（CLI，CommandLineInterface，CLImodemode2-1【Crtl+A【Crtl+E【Esc+F【Esc+B【Crtl+F【Crtl+B2-2雖然是命令行，CLI2-1，熟悉它們是熟練配置路由的部件間流動，流動如圖2-2所示。IOS2-3Cisco（PowerOnSelfTest，POST，診ROM（BootstrapLoader）BIOSBootstrapIOS裝到RAM序，取決于配置寄存器的啟動域以及其他的設(shè)置。配置寄存器（configurationIOS，2-2IOS2-42-2012-2-4路由器查找IOS網(wǎng)絡(luò)層協(xié)議的Cisco設(shè)備也可以獲得對方的信息。CDP協(xié)議默認(rèn)是啟動的。

用戶模式進(jìn)入到特權(quán)模式，“disable”命令則相反，在特權(quán)模式下的提示符為“#”。Translating"clok"...domainserver(55)Translating"clok"...domainserver%Unknowncommandorcomputername,orunabletofindcomputerclear%IncompleteRouter#clock?setSetthetimeandRouter#clockset?hh:mm:ssCurrentTimeRouter#clockset11:36:00%Incompletecommand.Router#clockset11:36:00?<1-31>Dayofthemonth MonthoftheRouter#clockset11:36:0012?MONTHMonthoftheyearRouter#clockset11:36:001208^%Invalidinputdetectedat'^'Router#clockset11:36:0012august%IncompleteRouter#clockset11:36:0012august2003Router#showclock11:36:03.149UTCTueAug12Router#?Execcommands: CreateatemporaryAccess-Listentry Applyuser-profiletointerfaceaccess-templateCreateatemporaryAccess-Listentry Erasea Exitfromthe Descriptionoftheinteractivehelp%Ambiguouscommand:"dis"disable“disconnect”。若再加多一個字母“a”就可以區(qū)分了。Router#configureterminalRouter#showhistoryconfshowhistoryconftshow使用表2-1的編輯鍵移動光標(biāo)Router#terminalhistorysizeRouter#terminalnoeditingRouter#terminal令先連接到R1路由器上：Router#configureterminalEnterconfigurationcommands,oneperline.EndwithCNTL/Z.Router(config)#hostnameR1R1(config)#enablepasswordciscoR1(config)#interfaceR1(config-if)#ipaddressR1(config-if)#noR1(config-if)#ipaddressR1(config-if)#noR1#copyrunning-configstartup-configDestinationfilenamestartup-config]?Buildingconfiguration...Enterconfigurationcommands,oneperline.EndwithCNTL/Z.Router(config)#hostnameR2R2(config)#enablepasswordciscoR2(config)#interfaceg0/0R2(config-if)#ipaddressR2(config-if)#noshutdownR2(config-if)#ipaddressR2(config-if)#clockrateR2(config-if)#noshutdownR2#copyrunning-configstartup-Destinationfilename[startup-config]?Buildingconfiguration...R2#pingTypeescapesequencetoSending5,100-byteICMPEchosto26,timeoutis2Successrateis100percent(5/5),round-tripmin/avg/max=1/1/4R2#showversionCiscoIOSSoftware,2800Software(C2800NM-ADVENTERPRISEK9-M),Version12.4(11)T1,RELEASESOFTWARE(fc5)TechnicalSupport:/techsupportCopyright(c)1986-2007byCiscoSystems,Inc.CompiledThu25-Jan-0712:50byROM:SystemBootstrap,Version12.4(1r)[hqluong1r],RELEASESOFTWARER2uptimeis4hours10minutesSystemreturnedtoROMbypower-onSystemimagefileis"flash:c2800nm-adventerprisek9-mz.124-IfyourequirefurtherassistancepleasecontactusbysendingemailtoCisco2821(revision53.50)with249856K/12288KbytesofProcessorboardIDFHK1039F1FG//主板系列號2GigabitEthernetinterfaces4Low-speedserial(sync/async)interfaces1VirtualPrivateNetwork(VPN)ModuleDRAMconfigurationis64bitswidewithparityenabled.239Kbytesofnon-volatileconfigurationmemory.62720KbytesofATACompactFlashConfigurationregisterisR2#showrunning-configBuildingconfiguration...Currentconfiguration:1238!versionservicetimestampsdebugdatetimemsecservicetimestampslogdatetimemsecnoservicepassword-encryption!hostname R2#showstartup-configBuildingconfiguration...Currentconfiguration:1238!versionR2#showinterfaceSerial0/0/0isup,lineprotocolisup HardwareisGT96KSerialInternetaddressis/24IPMTU1500bytes,BW128Kbit,DLY20000usec,reliability255/255,txload1/255,rxload1/255//注：以上是該接口的MTU、帶寬、延時、可靠性、負(fù)載大小EncapsulationHDLC,loopbacknotsetHDLCKeepaliveset(10sec) R2#showflashFile 41205996c2800nm-adventerprisek9-mz.124-[41206060bytesused,23019216available,64225276total]62720KbytesofATACompactFlash(Read/Write)R2#showcontrollerss0/0/0InterfaceSerial0/0/0HardwareisGT96KDCEV.35,clockrateidbat0x4728A8C0,driverdatastructureat0x4728CBECwic_info0x4728D218PhysicalPort1,SCCNumR2#showipHardware-3

2-7TFTPServerTftpSolarWindsTFTPServer2-8TFTP2-9TFTPServerSwitch#erasestartup-configR2(config)#intg0/0R2(config-if)#noR2(config-if)#ipaddressR2#pingTypeescapesequencetoSending5,100-byteICMPEchosto00,timeoutis2Successrateis100percent(5/5),round-tripmin/avg/max=1/1/4R2#copyrunning-configAddressornameofremotehost00//回答TFTPIPDestinationfilename[r2- 1381bytescopiedin0.452secs(3055FTPshowrunning-config”命令顯示當(dāng)前的配置，在終端窗口中復(fù)制全部配置，粘貼到某文本文件中。R2#showCompactFlashFile 41205996c2800nm-adventerprisek9-mz.124-[41206060bytesused,23019216available,64225276total]62720KbytesofATACompactFlash(Read/Write)Addressornameofremotehost Destinationfilename[c2800nm-adventerprisek9-mz.124-

Router#configureEnterconfigurationcommands,oneperline.EndwithCNTL/Z.Router(config)#hostnameR2R2(config)#enablepassword由器的啟動過程，進(jìn)入rommon模式，如下：SystemBootstrap,Version12.4(1r)[hqluong1r],RELEASESOFTWARE(fc1)Copyright(c)2005byciscoSystems,Inc.Initializingmemoryforc2821processorwith262144KbytesofmainMainmemoryisconfiguredto64bitmodewithECCenabledReadonlyROMMONinitializedrommon1>confregrommon2>退出setup模式。Router#copystartup-configrunning-configDestinationfilename[running-config]?661bytescopiedin0.625R2#configureterminalR2(config)#enablepasswordciscoR2(config)#config-register0x2102R2#copyrunning-configstartup-Destinationfilename[startup-config]?Buildingconfiguration...R2#showflash:CompactFlashFile 41205996c2800nm-adventerprisek9-mz.124-[41206060bytesused,23019216available,64225276total]62720KbytesofATACompactFlash(Read/Write)//顯示flash中的R2#deleteflash:c2800nm-adventerprisek9-mz.124-11.T1.binDeletefilename[c2800nm-adventerprisek9-mz.124-11.T1.bin]?2>3>4>5>6IOS，IPTFTP服務(wù)器在同一網(wǎng)段，是不需要網(wǎng)關(guān)的，但是不能不配置該值，所以我們把DEFAULT_GATEWAY胡亂地指向了TFTP服務(wù)器。請注意變量名的大小寫。rommon8>//開始從tftp恢復(fù)IP_ADDRESS:IP_SUBNET_MASK:DEFAULT_GATEWAY:TFTP_SERVER:TFTP_VERBOSE:ProgressTFTP_RETRY_COUNT:TFTP_TIMEOUT:7200TFTP_CHECKSUM:YesTFTP_MACADDR:00:19:55:66:63:20GE_PORT:GigabitEthernet0GE_SPEED_MODE:AutoInvokethiscommandfordisasterrecoveryWARNING:allexistingdatainallpartitionsonflashwillbelost!Doyouwishtocontinue?y/n:[n]:y//回答“y”開始從tftp服務(wù)器上恢復(fù)IOS，根據(jù)IOS的大小，通常需要十幾分鐘 00!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Filereceptioncompleted.Validatingchecksum.Copyingfilec2800nm-adventerprisek9-mz.124-11.T1.bintoflash.rommon9>

步驟1：打開接口R1(config)#intg0/0R1(config-if)#ints0/0/0R2(config)#intg0/0R2(config-if)#ints0/0/0R2(config-if)#clockrateR1#showGlobalCDPinformation:GlobalCDPinformation:SendingCDPpacketsevery60secondsSendingaholdtimevalueof180secondsSendingCDPv2advertisementsisenabled180秒R1#showcdpGigabitEthernet0/0isup,lineprotocolisupEncapsulationARPASendingCDPpacketsevery60secondsHoldtimeis180secondsGigabitEthernet0/1isadministrativelydown,lineprotocolisdownEncapsulationARPASendingCDPpacketsevery60secondsHoldtimeis180secondsSerial0/0/0isdown,lineprotocolisdownEncapsulationHDLCSendingCDPpacketsevery60secondsHoldtimeis180secondsSerial0/0/1isadministrativelydown,lineprotocolisdownEncapsulationHDLCSendingCDPpacketsevery60secondsHoldtimeis180secondsR1#showDeviceLocalPortSerRSSerGigSWS-FasceR1#showcdpentryDeviceID:R2Entryaddress(es):Platform:Cisco2821,Capabilities:RouterSwitchIGMPInterface:Serial0/0/0,PortID(outgoingport):Serial0/0/0Holdtime:158secVersionCiscoIOSSoftw