Grandmaster failover

What this PTP grandmaster failover question tests

This is an easy networking question about Precision Time Protocol (PTP) failover scenarios. It probes your understanding of how PTP domains respond when the active grandmaster loses synchronisation to an external time reference, and how the protocol's selection algorithm determines which candidate clock should assume the grandmaster role.

The question focuses on the Best Master Clock (BMC) algorithm and the priority and quality attributes that govern clock selection. Candidates should be familiar with how clock state changes propagate through a domain, what "eligible" means in the context of PTP clock quality, and the conditions under which a standby candidate is promoted to grandmaster status.

• PTP clock states and transitions
• Best Master Clock algorithm and selection criteria
• Clock quality attributes and eligibility rules
• Synchronisation loss detection and recovery