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. "Monolithic" in this context simply means that the image is composed of a single file that contains all of the relevant code and operational information. During bootup, this file is "unbundled" and moved into RAM from where it operates.

The disadvantage of Bundle Mode is that it uses more memory because it needs to extract the packages every time the device boots up. It doesn’t support software sub-package patching and doesn’t allow for Sub Package Installation.

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. The software image file includes separate packages for each feature. These packages are extracted from the bundle and copied to the flash memory during the install operation. The packages.conf file is automatically created and it keeps track of all installed packages.

The advantages of Install Mode are that it uses less memory and allows for Sub Package Installation (you can choose which packages you want to install). This mode also supports software sub-package patching without network downtime.

You can think of install mode as resembling an operating system installation like Linux or Windows which contains multiple files, packages, and registries. Conversely, bundle mode can be thought of more as a “firmware.”

Care should be taken when using either mode in conjunction with Stackwise

Links

https://networklessons.com/cisco/ccna-200-301/upgrade-cisco-ios-image