Users Guide

244 Stacking
In most cases, a switch that is added to an existing stack will become a stack
member, and not the stack master. When a switch is added to the stack, one
of the following scenarios takes place regarding the management status of the
new switch:
• If the switch has the stack master function enabled but another stack
master is already active, then the switch changes its configured stack
master value to disabled.
• If the stack master function is unassigned and there is another stack
master in the system then the switch changes its configured stack master
value to disabled.
• If the stack master function is enabled or unassigned and there is no other
stack master in the system, then the switch becomes stack master.
• If the stack master function is disabled, the unit remains a non-stack
master.
If the entire stack is powered OFF and ON again, the unit that was the stack
master before the reboot will remain the stack master 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.