Concept Guide

Stack Group/Port Numbers
By default, each unit in Standalone mode is numbered stack-unit 1.
A maximum of eight 10G stack links or four 40G stack links can be made between two units in a stack. The front end ports are divided into
18 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 17 are one 40G port each.
The front end ports accommodate SFP, SFP+ and QSFP+.
• Ports are divided into 18 stack-groups (0 to 17) 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 1-4, stack-group 1 corresponds to ports 5-8, so on through stack-group 11.
– stack-group 12 corresponds to the 40G port 49, stack-group 13 corresponds to port 50, so on through stack group 17.
Figure 127. Stack-Group Assignments
1
Stack-group 0 (Ports 1, 2, 3, and 4) 2 Stack-group 1 (Ports 5, 6, 7, and 8)
3 Stack-group 2 (Ports 9, 10, 11, and 12) 4 Stack-group 3 (Ports 13, 14, 15, and 16)
5 Stack-group 12 (Port 49) 6 Stack-group 14 (Port 51)
7 Stack-group 16 (Port 53) 8 Stack-group 17 (Port 54)
9 Stack-group 15 (Port 52) 10 Stack-group 13 (Port 50)
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 rmware 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 identies the unit, its Dell EMC Networking OS version, and its incompatibility for
rmware 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.
1000 Stacking