Reference Guide

• Ports are divided into 16 stack-groups (0 to 15) as shown in the following example. The stack groups must be of a
single speed - either all 10G or all 40G.
– stack-group 0 corresponds to ports 0-3, stack-group 1 corresponds to ports 4-7, so on through stack-
group 11.
– stack-group 12 corresponds to the 40G port 48, stack-group 13 corresponds to port 52, so on through
stack group 15.
Figure 119. S4820T Stack-Group Assignments
You can connect the units while they are powered down or up. Stacking ports are bi-directional.
With FTOS version 8.3.12.0, when a unit is added to a stack, the management unit performs a system check on the new
unit to ensure the hardware type is compatible. A similar check is performed on the FTOS version. If the stack is running
FTOS version 8.3.12.0 and the new unit is running an earlier software version, the new unit is put into a card problem
state.
• If the unit is running FTOS version 8.3.10.x, it is upgraded to use the same FTOS version as the stack, rebooted,
and joined the stack.
• If the new unit is running an FTOS version prior to 8.3.10.x, the unit is put into a card problem state, FTOS is not
upgraded, and a syslog message is raised. The unit must be upgraded to FTOS version 8.3.12.0 before you can
proceed.
Syslog messages are generated by the management unit:
• before the management unit downloads its FTOS version (FTOS 8.3.12.0 or later) to the new unit. The syslog
includes the unit number, previous version, and version being downloaded.
• when the firmware synchronization is complete.
• if the system check fails, a message such as a hardware incompatibility message or incompatible uboot version
is generated. If the unit is placed in a card problem state, the management unit also generates an SNMP trap.
• if the software version of the new unit predates FTOS version 8.3.12.0, the management unit puts the new unit
into a card problem state and generates a syslog that identifies the unit, its FTOS version, and its incompatibility
for firmware synchronization.
NOTE: You must enter the stack-unit stack-unit stack-group stack-group command when
adding units to a stack to ensure the units are assigned to the correct groups.
NOTE: Any scripts used to streamline the stacking configuration process must be updated to reflect the Command
Mode change from EXEC to CONFIGURATION to allow the scripts to work correctly.
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