Chapter9 Managing a Cisco Internetwork

The Router Boot Sequence 启动序列用来测试硬件和加载所必需的软件,包括以下几个步骤: POST,测试硬件 查找和加载 IOS 在 NVRAM 中查找有效的 startup-comfig 配置文件 NVRAM 里查找到了这个配置文件,router 就可操作;如果文件不存在,router 进到 setup 模式 | Chapter9 Managing a Cisco Internetwork The Internal Components of a Cisco Router Cisco Router W bootstrap WÆ ROM W microcode Æ Æ ftWW router M in IOS POST ROM WW WÎ WïœWW O ROM monitor ROM lW ftfflMTOW Mini-IOS Cisco R RXBOOT bootloader M ROM l IOS W W ios in m RAM random-access memory fô ARP É Î0 running-config I M router IOS WA RAM B ROM read-only memory router lE ft Flash memory W Æ IOS S router MM l W M l È Intel ftj l EEPROM NVRAM nonvolatile RAM startup-config ft router OB W ifrM W W configuration register fê router nM M M MÎÆ show version 0x2102 16 XM W router AW Mi IOS A NVRAM fCM- 0 The Router Boot Sequence W iWttWm WWM 1. Æ fî posww 2. bootstrap i IOS NVRAM TOWl startup-comfig K 4. hMÆ NVRAM M TS ft router OM ft Æ router S lj setup Managing Configuration Registers Cisco l router W 1 NVRAM 16 iu W configuration S 0x2102 AW in IOS A NVRAM K Understanding the Configuration Register Bits ÆWUWt 1. 0 glj 3 g 2. 6 M NVRAM 3. 8 M BREAK 00 glj 03 1. SÆ 00 ROM monitor M ÀllJS M configuration register Wtf SÆ router W rommon A b Solaris W OpenBoot 1 2. Æ 01 ROM W M configuration register Wtf SÆ 2101 router boot 3. - SÆ 02 glj 0F AIM Æ NVRAM g Checking the Current Configuration Register Value show version A configuration register W ÎÉ W T P S M mW mflWim Changing the Configuration Register MWA configuration register Wtf router W S .Æ M S T Æ config-register W .W tf 0x101 â ffift T Router config config-register 0x101 Router config AZ Router sh ver të Configuration register is 0x2102 will be 0x0101 at next reload W WfWA W W K AA Recovering Passwords W Mm timW 6 WW NVRAM MW W W MUM 0x2102 WM WM 0x2142 OTWtë NVRAM MmiWWW 1Æ router W BREAK 2. configuration register Wflï fzi ÏJV 0x2142 3. 4. Àt Î 5. startup-config A 1 running-config 6. fê 7. configuration register W 0x2102 8. wrn 9. B M W 2500 Jft 2600 WM1 1 Æ 2600 WJWWmOT Ctrl BREAK 1 Pffi . V monitor command boot aborted due to user interrupt. T System Bootstrap Version 2 XA4 RELEASE .