IOS Images

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IOS Images

• Shawn Shuoh-Ren Tsai
• Cisco Academy Training Center
• David Ta-Wei Shih
• CGUIC

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IOS Software

• Boot system command
• Examine the configuration register setting in
  NVRAM to see if a particular source for the IOS
  has been designated.
• Routers boot Cisco IOS software from
• Flash memory
• TFTP server
• ROM (not full Cisco IOS software)

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Configuration Register Value

• change the default configuration register setting
  with the global configuration-mode
• Config-register
• 0x---0
• Use ROM monitor mode (manually boot using the b
  command)
• 0x---1
• Automatically boot from ROM (default if router
  has no Flash)
• 0x---x to 0x---F
• Examine NVRAM for boot system commands (0x---2 is
  the default if the router has FLASH)

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Boot System Commands

• You can enter multiple boot system commands to
  specify the fallback sequence for booting Cisco
  IOS software
• router(config) boot system flash
  gsnew-imagerouter(config) boot system tftp
  test.exe 172.16.13.11router(config) boot system
  rom

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Show flash commands

• verify that you have sufficient memory on your
  system
• It is a good idea to keep a backup copy of the
  IOS image file for each router.
• Copy flash tftp
• Copy tftp flash

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IOS Naming Convention

• The naming convention for Cisco IOS Release 11.2
  contains three parts 
• the platform on which the image runs 
• a letter or series of letters identifies the
  special capabilities and feature sets supported
  in the image 
• specifics as to where the image runs and whether
  it has been zipped or compressed 

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