How is the Root Bridge elected in STP?

The Root Bridge in Spanning Tree Protocol (STP) is elected based on the lowest Bridge ID (BID). The Bridge ID is a combination of the Bridge Priority value and the MAC address of the switch. When STP begins the election process, all switches in the network participate by sending Bridge Protocol Data Units (BPDUs) containing their own Bridge IDs.

A switch with the lowest Bridge ID becomes the Root Bridge. The Bridge Priority can be set by administrators to influence the election, with a lower Bridge Priority leading to a higher chance of being elected as the Root Bridge. However, if two switches have the same Bridge Priority, the switch with the lower MAC address becomes the Root Bridge.

The correct answer highlights the automatic nature of this process, where switches use their Bridge IDs to determine the leader in a loop-free topology. This mechanism ensures that there is a single point of reference in the network, minimizing confusion and ensuring efficient data communication. Other methods, such as manual configuration or exclusive reliance on MAC addresses, are not part of the standard STP election process.