Cisco 3850 Software Upgrade Bundle Mode. By default the switches are shipped in Install mode. ISSU helps network administrators avoid a network outage when performing a software upgrade.
Bundle Mode The Bundle mode uses the monolithic Cisco IOS images to boot a switch. To do this execute the command below in exec. 3850 software expand running to flash.
Catalyst 3850-12S-E Switch.
There are 2 methods of booting and running IOS XE software in 3850 switchstack. A full stack reload is not necessary. ISSU helps network administrators avoid a network outage when performing a software upgrade. The method that you use to upgrade Cisco IOS XE software depends on whether the device is running in installed mode or in bundle mode.