IOS install mode vs bundle mode

IOS XE switches support two modes for the operation of the IOS: Bundle mode and install mode.

Bundle mode - This is the traditional way in which Cisco IOS operates using a single monolithic .bin file. During bootup, this file is "unbundled" and moved into RAM from where it operates. This mode uses more RAM.

Install mode - This mode is the default mode for most modern Cisco devices. It uses a "package provisioning" file named packages.conf in order to boot the switch. Additionally, there are several .pkg files in the flash that are used.

When used in conjuction with StackWise:

  • all switches in the stack should be configured with the same mode
  • all switches in the stack should have the same license as the active switch
  • when upgrading the IOS in install mode, simply upgrade the active switch, and all switches will be upgraded
  • when upgrading the IOS in bundle mode, the IOS file must be copied to each switch in the stack