What is the role of the Root Bridge in STP?

• A. To act as the central repository for all updates in the STP topology database; the bridge with the 'lowest' or best bridge ID
• B. It forwards frames to all devices
• C. It locks ports to prevent changes
• D. It assigns IP addresses to devices

Answer: (A)

In STP, a Root Bridge is the reference point for the entire spanning-tree topology. It is chosen as the switch with the lowest Bridge ID, which combines a configured priority with the switch’s MAC address. Because that switch has the smallest ID, all other switches compute their best path toward it, and a Root Port on each non-root switch points toward the root. Since the root acts as the center of the tree, every port on the Root Bridge becomes a Designated Port for its connected segment, meaning those ports are used to forward frames into the network toward other switches and devices. There is no Root Port on the Root Bridge, and the bridge does not handle IP address assignment. The fundamental idea is that the Root Bridge provides a single, authoritative reference that guides the entire spanning-tree calculation.