NOTE: If the stacked switches all reboot at approximately the same time, the switch with the highest
MAC address is automatically elected as the master switch. The switch with the next highest MAC
address is elected as standby. As each switch joins the stack, it is assigned the lowest available
stack-unit number from 0 to 5. The default configuration of each stacked switch is stored in the
running configuration of the stack. The stack-unit ID numbers are retained after future stack
reloads.
To verify the stack-unit number assigned to each switch in the stack, use the show system brief
command.
To configure stacked switches so that stacking roles are determined by preset priorities, use the stack-
unit priority command (refer to Assigning a Priority to Stacked Switches).
Assigning a Priority to Stacked Switches
To configure the stack so that the roles are assigned according to pre-determined priorities instead of
using the highest MAC addresses, use the stack-unit priority command in Global Configuration
mode on each stacked switch.
The switch with the highest priority number is elected master. The switch with the next highest priority
number is elected standby and takes over stack management if the master switch fails.
Configure the priority of stacked switches to determine stack mastership.
CONFIGURATION mode
stack-unit unit-number priority number
•stack-unit unit-number identifies the switch in the stack.
•priority priority-number specifies the management priority.
The valid range is from 1 to 14.
The default is 0.
To revert the management priority of a stack unit to the default value of 0, use the no form of the stack-
unit unit-number priority number command.
After you reconfigure the priorities of stacked switches, reload the stack so that a new master and
standby election is performed.
Renumbering a Stack Unit
To renumber a stack unit to reset the unit numbering for a master, standby or member unit, use the
following command.
• If you renumber the master switch, you are prompted to reload the entire stack.
• If you renumber the standby switch, only the switch reloads and is replaced by a member switch that
is elected as the new standby.
• If you renumber a member switch, only the member switch reloads.
892 Stacking