Reference Guide

Enabling Front End Port Stacking
To enable the front ports on an S4820T unit for stacking, use the following commands.
NOTE: After a port has been allocated for stacking, you can only use it for stacking. If stack-group 0 is allocated for
stacking, you can use ports 0, 1, 2, and 3 for stacking but not for Ethernet anymore. If only port 0 is used for
stacking, ports 1, 2, and 3 are spare; they cannot be used for Ethernet.
1. Assign a stack group for each unit.
CONFIGURATION mode
stack-unit id stack-group id
Begin with the first port on the management unit. Next, configure both ports on each subsequent unit. Finally, return
to the management unit and configure the last port.
The range is from 0 to 15.
2. Save the stacking configuration on the ports.
EXEC Privilege mode
write memory
3. Reload the switch.
EXEC Privilege mode
reload
FTOS automatically assigns a number to the new unit and adds it as member switch in the stack.
The new unit synchronizes its running and startup configurations with the stack.
4. After the units are reloaded, the system reboots. The units come up in a stack after the reboot completes.
To view the port assignments, use the show system stack-unit command.
Creating a New Stack
Prior to creating a stack, know which unit will be the management unit and which will be the standby unit.
Enable the front ports of the units for stacking. For more information, refer to Enabling Front End Port Stacking.
To create a new stack, use the following commands.
1. Power up all units in the stack.
2. Verify that each unit has the same FTOS version prior to stacking them together.
EXEC Privilege mode
show version
3. Manually configure unit numbers for each unit, so that the stacking is deterministic upon boot up.
EXEC Privilege mode
stack-unit 0 renumber
Renumbering causes the unit to reboot. The stack-unit default for all new units is stack-unit 0.
4. Configure the switch priority for each unit to make management unit selection deterministic.
CONFIGURATION mode
stack-unit priority
5. Assign a stack group for each unit.
CONFIGURATION mode
stack-unit id stack-group id
Begin with the first port on the management unit. Next, configure both ports on each subsequent unit. Finally, return
to the management unit and configure the last port. (refer to the following example.)
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