VSF Fast Software Upgrade

Fast Software Upgrade (FSU) is a feature in VSF stacking which enables users to upgrade switch software with minimal down-time of links by rebooting the standby to boot with the upgraded image while the current commander and its IMs are still intact and forwarding traffic. The traditional software upgrade of a VSF stack consists of:

• Copying the switch software image through a CLI command on to the switch primary or secondary bank.

• Rebooting the entire stack for all members to boot with the newly upgraded SW image.

The down-time of links is longer because when the whole stack reboots, all IMs, on all members, are down during the time of reboot and stack formation.