Which option best describes the function of a BPDU in networking?

• A. Determine the topology of the network.
• B. Encrypt data transmissions.
• C. Provide DNS resolution.
• D. Assign IP addresses automatically.

Answer: (A)

BPDU messages carry topology information used by the Spanning Tree Protocol to prevent loops and determine the network’s active path. They include details like which switch is the root, the path cost to the root, and which ports should forward or block traffic. By exchanging BPDUs, switches elect a root bridge and assign port roles, shaping a loop-free tree that data can move through safely. That’s why this option best describes the function of a BPDU. BPDUs aren’t used to encrypt traffic, resolve DNS, or auto-assign IP addresses—those tasks are handled by other protocols and mechanisms.