Flash Image Download and Update

Note: The flash image download and update process only occurs when the client device reboots, or when the DHCP client has been disabled and then re-enabled.

Once a lease is obtained from the server, the device compares the file name of the requested flash image with the image stored in flash memory. In a stacking configuration, the device compares the file name with the image stored in the Active Controller only.

  • If the .bin file names match, then the DHCP client skips the flash image download. If auto-provisioning is enabled, the DHCP client proceeds with downloading the configuration files.
  • If the .bin file names are different, then the DHCP client downloads the new image from a TFTP server and then writes the downloaded image to flash memory. In a stacking configuration, the device copies the flash image to flash in all stack member units.

The code determines which flash (primary or secondary) to use based on how the device is booted. In a stacking configuration, the member units use the same flash as the Active Controller. Once the flash is updated with the newer flash image, the device is reloaded, and any member units in a stacking configuration are reloaded as well. If auto-provisioning is enabled, the DHCP client then proceeds to download the configuration files.

Parent topic: Configuration Notes and Feature Limitations for DHCP Auto-Provisioning