Cisco Certified Network Professional 2026 – 400 Free Practice Questions to Pass the Exam

Root Guard plays a crucial role in Spanning Tree Protocol (STP) by ensuring the stability of the network topology. It is specifically designed to prevent a non-root switch from becoming the root bridge in a network segment where a switch has been designated as the root bridge.

When Root Guard is enabled on a port, it effectively protects the port from receiving BPDUs (Bridge Protocol Data Units) that indicate a superior root bridge. If a BPDU that declares a new root is received on the guarded port, Root Guard will block the port, thereby preventing any misconfiguration or unintended behavior that could disrupt the existing STP topology. This is essential in maintaining the intended design and ensuring optimal network performance.

The correct answer highlights the significance of Root Guard in managing which devices can contribute to the root bridge election process, thereby maintaining the integrity of the network's designated root. This functionality is crucial for preventing loops and ensuring that the correct logical topology is maintained.