??????IOS ??

1
??????IOS ??

• 1?????????????,?????????????
• 2?????????,???????????
• 3?????????????????,????PC ???,????CPU????BOOT
  ROM??
• 4?????????????????????,?????NVRAM?FLASH
  ??????????

2
????6???????

• (1) CPU??????,??????,??????????????
• (2) RAM/DRAM??,???????????,?????ARP
  ?????????????????????????RAM ?????????????????
• (3) FLASH????????ROM,????????IOS,FLASH
  ???????????????IOS ????????????????????,FLASH
  ????????FLASH ?????,???????IOS ???
• (4) NVRAM????RAM,????????????,??????,NVRAM
  ?????????
• (5) ROM?????,????????????????????????IOS
  ??(?????????),ROM ?????????????
• (6) ??(Interface)??????,???????????????????????

3
IOS ??

• ????????????,????IOS(Internetwork Operating
  System)?
• ???????????IOS ????
• Cisco ?IOS??????(??CLI,Command Line
  Interface),CLI ?????????
• (1) ????(User mode)??????????????????,??????????,
  ????????????????
• (2) ????(Privilege mode)??????????,??????????????
  ??

4

• ?CLI ?????show??????????????????,???1?

5
?1 show????????????
6
????????

• ???????????,????????NVRAM ?,????????????
• ????,????TFTP ???????????????????????????????????,
  ???2 ???
• ????IOS ?????,?????????TFTP ????IOS ????????
• ?????????,???????????IOS,?????????,????TFTP???????
  IOS ??????????????????,????????

7
? 2 ???????
8
????????

• Cisco ??????,????????????(Power On Self
  Test,POST),????CPU????????????,??????????????????3
  ,?????

9

• (1) ??ROM ????????(Bootstrap Loader),???????BIOS
  ???,Bootstrap ??IOS ??RAM ?
• (2) IOS ?????????(FLASH?TFTP ?????ROM ?),?????IOS
  ?????,?????????????????????????(configuration
  register)???16 ?(2 ??)????,?4 ??????,?????????????
  ?IOS,???1????IOS ???????4 ???
• (3) ??IOS ?RAM ???IOS ?????,?????
• (4) ?NVRAM ???????,?????????RAM ????
• (5) ???NVRAM ?????????,???setup ????(?????????)?

10

• ? 1 ???????????

???????(16 ??) ??
0 ??ROM ??
1 ???ROM ???
2-F ?FLASH ?TFTP ?????
11
?4? 2-4 ?????IOS ?????