On a network operating with STP, how many types of RSTP BPDUs are defined?

In a network operating with Rapid Spanning Tree Protocol (RSTP), there are two types of Bridge Protocol Data Units (BPDUs) defined: the Configuration BPDU and the TCN (Topology Change Notification) BPDU. The Configuration BPDU is used to convey information about the network topology, including the bridge IDs and port roles, while the TCN BPDU is specifically utilized to inform other switches of topology changes, allowing the network to react accordingly.

Understanding this distinction is crucial because it highlights how RSTP is designed to enhance the traditional Spanning Tree Protocol (STP) by allowing for rapid convergence and efficient handling of topology changes. In contrast to that, stating there is only one type of BPDU misses the complexity and functionality of RSTP in managing network changes and maintaining stability. The correct interpretation recognizes the two types, ensuring a deeper comprehension of RSTP's operational mechanisms.