White Papers

Create a Stack
Stacking is enabled on the device using the front end ports.
Stack Group/Port Numbers
By default, each unit in Standalone mode is numbered stack-unit 0.
A maximum of eight 10G stack links or two 40G stack links can be made between two units in a stack. The front end ports are
divided into 16 stack groups, each with 40G of bandwidth. Stack groups 0 through 11 correspond to 10G stack groups with four
ports each. Stack groups 12 to 15 are one 40G port each.
The front end ports accommodate SFP, SFP+ and QSFP+.
● 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 126. Stack-Group Assignments
You can connect the units while they are powered down or up. Stacking ports are bi-directional.
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 Dell EMC Networking OS version. If the stack is running Dell EMC Networking
OS 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 Dell EMC Networking OS version 8.3.10.x, it is upgraded to use the same Dell EMC Networking OS
version as the stack, rebooted, and joined the stack.
● If the new unit is running an Dell EMC Networking OS version prior to 8.3.10.x , the unit is put into a card problem state, Dell
EMC Networking OS is not upgraded, and a syslog message is raised. The unit must be upgraded to Dell EMC Networking
OS version 8.3.12.0 before you can proceed.
Syslog messages are generated by the management unit:
● before the management unit downloads its Dell EMC Networking OS version 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 Dell EMC Networking OS 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 Dell EMC Networking OS 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.
Stacking 831