Users Guide

Stacking 259
• If the management unit in the stack function is disabled, the unit remains
a non- management unit in the stack .
If the entire stack is powered OFF and ON again, the unit that was the
management unit in the stack before the reboot will remain the management
unit in the stack after the stack resumes operation.
The unit number for the switch can be manually configured. To avoid unit-
number conflicts, one of the following scenarios takes place when a new
member is added to the stack:
• If the switch has a unit number that is already in use, then the unit that is
added to the stack changes its configured unit number to the lowest
unassigned unit number.
• If the added switch does not have an assigned unit number, then the
switch sets its configured unit number to the lowest unassigned unit
number.
• If the unit number is configured and there are no other devices using the
unit number, then the switch starts using the configured unit number.
• If the switch detects that the maximum number of units already exist in
the stack making it unable to assign a unit number, then the switch sets its
unit number to
unassigned and does not participate in the stack.
Adding a Switch to the Stack
When adding a new member to a stack, make sure that only the stack cables,
and no network cables, are connected before powering up the new unit. Stack
port configuration is stored on the member units. If stacking over Ethernet
ports (Dell EMC Networking N1100-ON and N1500 Series only), configure
the ports on the unit to be added to the stack as stacking ports and power the
unit off prior to connecting the stacking cables. Make sure the links are not
already connected to any ports of that unit. This is important because if STP
is enabled and any links are UP, the STP reconvergence will take place as soon
as the link is detected.
After the stack cables on the new member are connected to the stack, the
units can be powered up, beginning with the unit directly attached to the
currently powered-up unit. Always power up new stack units closest to an
existing powered unit first. Do not connect a new member to the stack after it
is powered up. Never connect two functional, powered-up stacks together.
Hot insertion of units into a stack is not supported.