Question

Unlike OSPF which uses the highest IP to determine the RID, STP uses the _________ Bridge ID to determine the root bridge.

1) Lowest
2) Highest
3) Random
4) None of the above

Answer 1

STP uses the Lowest Bridge ID to determine the root bridge, which is a combination of bridge priority and the device's MAC address. The selection is based on the Lower Bridge ID as opposed to OSPF, which uses the highest IP address as the Router ID.

Step-by-step explanation:

The Spanning Tree Protocol (STP) uses the Lowest Bridge ID to determine the root bridge. This Bridge ID is a combination of a bridge priority value and the MAC address of the device. When STP-enabled switches start up, they exchange Bridge Protocol Data Units (BPDUs) to elect the root bridge based on the Lowest Bridge ID. The root bridge serves as the central point of reference for all path calculations within the network to prevent loops. Therefore, the correct answer to the question is 1) Lowest. In contrast, Open Shortest Path First (OSPF) uses the highest IP address of all the router's interfaces or a manually configured Router ID (RID).