Support for in-service software upgrades
Refer to the respective NOS-version release notes for ISSU and upgrade-path information. An ISSU allows a dual management module system or Top of Rack switches to be upgraded non-disruptively and is invoked by entering the firmware download command from the active management module. ISSU is not supported in NOS 6.0.0 from previous NOS versions. Use the coldboot or manual options of the firmware download command.
High Availability behavior during ISSUs is the same as that of warm recovery described in HA failover. For more information, refer to the “Upgrading firmware on a modular chassis” of the Network OS Upgrade Guide.