Cisco ENCOR Practice Exam 2025 – All-in-One Comprehensive Guide to Mastering Enterprise Network Core Technologies!

In a Layer 2 network, the TCN (Topology Change Notification) BPDU (Bridge Protocol Data Unit) plays a critical role in managing changes to the network topology. When a switch detects a change in the network topology—such as a port going up or down—it generates a TCN BPDU. This notification is then sent to other switches in the network to inform them about the topology change.

The significance of this communication lies in its ability to prompt all switches to enter a state of reconvergence. This means that they will re-evaluate their spanning tree structure to ensure that the network remains loop-free and optimized for data transmission. The TCN BPDU effectively facilitates the maintenance of a stable and efficient Layer 2 network by ensuring all switches are aware of changes that could affect data flow.

In contrast, the other options do not accurately reflect the purpose of TCN BPDUs. Data packet transmission, for example, pertains to the actual forwarding of traffic across the network rather than topology management. Layer 3 routing updates involve higher-level protocols that deal with routing information and are not relevant to Layer 2 operations. Lastly, network device configurations relate to the setting and management of device parameters rather than the communication of topology changes. Hence, the