Electing a Commander

In those cases in which the Commander of the stack is not identified, the stack undergoes a Commander Election process. This occurs when the entire stack is rebooted simultaneously, such as during a building power failure recovery, or when the stack becomes split and the Commander is isolated in the Inactive fragment, requiring the Active fragment to elect a new Commander.

All of the switches go through discovery and election at the same time. There is an election timer that is set for 60 seconds, and if there are no new switches discovered during that timeout period, the switches in the stack enter the election phase.

During the election process, for each group of switches that has the same STACK-ID (they should all be the same), these steps occur:

  1. The switches with the highest Stack Revision are discovered.

  2. The switch with the highest configured priority is selected as the Commander.

  3. If there are switches with the same “highest” priority, the switch that was the previous Commander is selected.

  4. If no switches were previous commanders, the switch that was the previous Standby is selected.

  5. If none of the above conditions apply, the switch with the lowest MAC Address is selected as the Commander.