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1、来自 中国最大的资料库下载Managing a Cisco Internetwork来自 中国最大的资料库下载Overview1.0 The Internal Components of a Cisco Router2.0 The Router Root Sequence3.0 Managing Configuration Registers4.0 Backing Up and restoring the Cisco IOS5.0 Backing Up and Restoring the Cisco Configuration6.0 Using Cisco discovery Protoc
2、ol7.0 Using Telnet8.0 Resolving hostnames9.0 Checking Network Connectivity来自 中国最大的资料库下载1.0The Internal Components of a Cisco RouternBootstrapnPOST (power-on self test)nROM monitornMini-IOSnRAM (random access memory)nROM (read-only memory)nFlash MemorynNVRAM (nonvolatile RAM)nConfiguration register来
3、自 中国最大的资料库下载2.0The Router Boot Sequence1.POST - to verify all components of the device are operational and present2.Bootstrap a program in ROM to look for and load the IOS (flash memory by default)3.After the IOS is loaded, it will look for a valid configuration file stored in NVRAM (startup-config
4、)4.If startup-config file is in NVRAM, the router will load and run this file; otherwise start the setup mode来自 中国最大的资料库下载2.1RAM for Working StorageWhen router is turned onnbootstrap program executed from ROMnload Cisco IOS software into memorynStores active configuration file, tables of networks m
5、ap and routing address listsnConfiguration file is in ASCIInSaved version in NVRAMnOperating system image in binary executable formCommand ExecutiveInternetwork Operating SystemProgramsActive Configuration FileTablesBufferBootstrap Program ExecutesRAMBackup of Config. FileIOSInterfaceNVRAM Flash来自
6、中国最大的资料库下载2.2Boot Sequence in detailsnPower-up self testnGeneric bootstrap loader executes from ROMnO.S. source determined from the boot field of configuration register. Boot field indicates Flash or network load, boot system commands in configuration file indicates the exact location of image.nO.S.
7、 image loaded into low-addressed memory. Hardware, software components and lists on the console terminalnSaved configuration file in NVRAM is loaded into main memory, and execute one line at a timenIf no valid configuration file exists in NVRAM, operating system executes a question-driven initial co
8、nfiguration routine referred to as the system configuration dialog. This special mode is also called setup dialog 来自 中国最大的资料库下载2.3Commands relate to StartupnRouter# show startup-config (show config)nRouter# show running-config (write term)nRouter# erase startup-config (write erase)nRouter# reload (
9、reset the router)nRouter# setup (start the setup mode)来自 中国最大的资料库下载2.3Commands showing Router Status (show)nShow Version - configuration of the system hardware, software version, names and sources of configuration files and boot images.nShow Processes - Information about active processesnShow Proto
10、cols - Configured protocolsnShow Mem - Statistics about routers memorynShow Stacks - Stack use of processes and interrupt routines, reason for last system rebootnShow Buffers - Statistics for buffer poolsnShow Flash - Information about flash memory devicenShow running-config - Active configuration f
11、ilenShow startup-config - Backup configuration filenShow Interfaces - statistics for all interfaces configured on router来自 中国最大的资料库下载2.4Showing Status commands for Cisco IOS Release 10.3 and Earliernwrite terminal - show running-confignshow config - show startup-config来自 中国最大的资料库下载3.0Managing Conf
12、iguration Registers3.1 Understanding the Configuration Register Bits3.2 Checking the Current Configuration Register Value3.3 Changing the Configuration Register3.4 Recovering Passwords来自 中国最大的资料库下载3.1Understanding the Configuration Register BitsConfiguration Register (four 4-bit hex) 2102 151413121
13、1109876543210 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 Boot Field: 0 - ROMmode; 1 Boot Image from ROM; 2 - Full boot process, load Cisco IOS software from Flash memory 3 to F Specifies a default boot filename (related to bit 13) Ignore NVRAM contentsBreak disabled; however, a break can be sent in the first 6
14、0 seconds while the system reboots, regardless of the configuration settings. IP broadcast with all zerosConsole line speedBoot default ROM software if network boot failsIP broadcasts do not have net numbersEnable diagnostic messages and ignore NVRAM contents来自 中国最大的资料库下载3.2Checking the Current Con
15、figuration Register ValuenUse show version command to see the current value of the configuration registersnCommon configuration values:l0x2102 the default value which means bits 13, 8 , 1 are on (boot default ROM software, break disabled and look for /load a router configuration file stored in NVRAM
16、 (the startup-config)l0x2142 register value for recovering passwords (bit 6 is turned on)来自 中国最大的资料库下载3.3Changing the Configuration RegisternTo modify how the router boots and runs.nTo change the register value, use the following commands either from the global configuration mode or the bootstrap prompt ( RO
