A company has a stack system consisting of three switches that is running stably. Now the main switch has restarted due to a fault. Which of the following descriptions of this phenomenon are…

Question

Options

• ABefore the original master switch is restarted, the original backup switch will be designated as the new backup switch.
• BAfter the original master switch is restarted, the original backup switch will become the new slave switch.
• CAfter the original master switch is restarted, the original master switch will become the new master switch.
• DAfter the original master switch is restarted, the original backup switch will be upgraded to the new master switch.

• A
  10% (2)
• B
  81% (17)
• D
  10% (2)

Explanation

In a 3-switch stack system (Master, Backup, Slave), when the master fails and restarts, the backup switch immediately takes over as the new master and the slave promotes to new backup - this is standard stack failover behavior. When the original master finishes restarting and rejoins, it does not reclaim its original role; instead, it rejoins as a slave, deferring to whichever switch is currently acting as master.

Why B is incorrect: After the original master restarts, the original backup does not become a slave - it became master during the failover and retains that role.

Why C is incorrect: The original master does not automatically reclaim the master role upon restart - it rejoins at the lowest rank (slave), since the stack has already elected a new master.

Why A and D are correct: Before the original master comes back online, the failover has already occurred (backup → master), and after the restart completes, the original backup remains the new master - which is exactly what D describes.

Memory tip: "Once dethroned, start from scratch." The original master loses its crown permanently upon failure and must rejoin as a commoner (slave); the original backup keeps the throne it earned during the crisis.

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