Which attribute must be configured within the spanning-tree protocol to ensure a new switch is the root bridge?

To ensure that a new switch is designated as the root bridge within the spanning-tree protocol, configuring the bridge priority attribute is essential. The bridge priority is used in the election process of the root bridge. When switches run the spanning-tree protocol, they assign themselves a priority value, which combined with their MAC address, helps determine which switch will be the root bridge.

The root bridge is the central point of the spanning-tree topology, serving as a reference for all other switches in the network. By default, all switches have a priority value of 32768. Lowering the bridge priority of a switch means it will be more likely to become the root bridge, as spanning-tree chooses the switch with the lowest priority value. If two switches have the same priority, then the switch with the lowest MAC address will become the root bridge.

Other attributes like root-id, port-id, and system MAC address play roles in spanning-tree operations, but they do not directly influence the selection of the root bridge in the same way that configuring the bridge priority does. The root-id is determined by the election process rather than being a configurable attribute, the port-id is relevant for determining the role of individual ports on switches, and the system MAC address is used as a tieb