Administrator Guide

• A stack unit can also enter a Card-Problem state after a split-stack reload in which a unit that was previously neither the master
nor standby is elected as the new master and has logical stack-unit provisioning congured for a stack-unit number that creates
a mismatch with the stack-unit numbering on other units.
Converting 4x10GbE Ports to 40GbE for Stacking
Stacking is supported only on 40GbE links by connecting 40GbE ports on the base module or a 2-Port QSFP+ module.
However, on a 2-Port 40GbE QSFP+ module, the ports operate by default in 4x10GbE (quad) mode with breakout cables as eight
10GbE ports.
Change a port from 4x10GbE to 40GbE mode of operation for stacking.
no stack-unit port portmode quad
After you convert the 4x10GbE ports to 40GbE, you must save the conguration and reload the stack for the change to take
eect.
• stack-unit unit-number is the unit ID number in the stack unit. The valid range is from 0 to 5.
• port port-number species the port number of the QSFP+ port to be converted to 40GbE mode. The valid values are:
base-module ports: 33 or 37; slot 0: 41 or 45; slot 1: 49 or 53. As shown below, portmode quad identies the port as a
split 10GbE SFP+ port.
Example of the no stack-unit port portmode quad Command
Dell(conf)# no stack-unit unit-number port port-number portmode quad
To display the stack-unit number, use the show system brief command.
Removing a Port from the Stacking Mode
To remove a 40GbE port from the stack, use the no form of the stack-unit unit-number stack-group number
command.
After entering the command, save the conguration and reload the stack for the change to take eect.
Remove a stacked port from a stack.
CONFIGURATION mode
no stack-unit unit-number stack-group group end write memory reload
When the reload completes, the port comes up in 40GbE mode if it is on the base module and in 4x10GbE (quad) mode if the port is
on a FlexIO module, such as a 2-Port 40GbE QSFP+ module.
Removing a Switch from a Stack
To remove a switch from a stack, disconnect the stacking cables from the unit either when the unit is powered on or o and is online
or oine.
After you remove all 40GbE ports from a stack (Removing a Port from the Stacking Mode), the switch functions in standalone mode
but retains the running and startup conguration that was last synchronized by the master switch while it operated as a stack unit.
If you remove a unit from the middle of a stack, the stack is split into multiple parts. Each split stack forms a new stack according to
MAC addresses or assigned priorities, as described in Conguring and Conguring and Bringing Up a Stack and Assigning a Priority
to Stacked Switches.
Adding a Stack Unit
You can add a new unit to an existing stack both when the unit has no stacking ports (stack groups) congured and when the unit
already has stacking ports congured.
If the units to be added to the stack have been previously used, they are assigned the smallest available unit ID in the stack.
Stacking
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