Power-On Sequence For Switch Stacks - Cisco Catalyst 9200 Series Hardware Installation Manual

Installing the Switch
Figure 14: Example of a Partitioned Data Stack with a Failover Condition

Power-On Sequence for Switch Stacks

Consider these guidelines before you power on the switches in a stack:
• The sequence in which the switches are first powered on might affect the switch that becomes the stack
• There are two ways to elect an active switch:
• Power off a switch before you add it to or remove it from an existing switch stack. If changes are made
• A stack split can occur on a full ring stack if:
• A stack split can occur in a partial ring stack if:
master.
• If you want a particular switch to become the active switch, configure it with the highest priority.
Among switches with same priority, the switch with the lowest MAC address becomes the active
switch.
• If you want a particular switch to become the active switch, power on that switch first. This switch
remains the active switch until a reelection is required. After 2 minutes, power on the other switches
in the stack. If you have no preference as to which switch becomes the active switch, power on all
the switches in the stack within 1 minute. These switches participate in the active switch election.
Switches powered on after 2 minutes do not participate in the election.
to the stack without powering down the switches, the following results can occur:
• If two operating partial ring stacks are connected together using a stack cable, a stack merge can
take place. This situation reloads the whole stack (all switches in the stack).
• If some switches in the stack are completely separated from the stack, a stack split can occur.
• More than one running switch is removed without powering down.
• More than one stack cable is removed without powering down.
• A switch is removed without powering down.
Cisco Catalyst 9200 Series Switches Hardware Installation Guide
Power-On Sequence for Switch Stacks
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