On which switchports should BPDU guard be enabled to enhance STP stability?

On which switchports should BPDU guard be enabled to enhance STP stability?

• A. All PortFast-enabled ports
• B. All VLAN trunks
• C. All access ports
• D. All switch management interfaces

Answer: (A)

BPDU guard should be enabled on all PortFast-enabled ports to enhance Spanning Tree Protocol (STP) stability. When a switch port is configured with PortFast, it transitions immediately to the forwarding state, bypassing the usual STP listening and learning states. This is particularly useful for ports connected to end devices like computers or printers, where there should be no BPDUs (Bridge Protocol Data Units) received. Enabling BPDU guard on these ports mitigates the risk of receiving unexpected BPDUs that could cause STP topology changes, leading to network loops or instability. If a BPDU is detected on a PortFast-enabled port, BPDU guard will shut the port down, thus maintaining the integrity of the spanning tree and preventing potential loops in the network. On the other hand, enabling BPDU guard on VLAN trunks, access ports, or switch management interfaces does not address the primary concern of unexpected BPDUs in the context of PortFast ports. VLAN trunks are designed to carry BPDUs for all VLANs across connected switches and should not be configured with BPDU guard, as this would disrupt the transmission of these important control messages. Access ports not configured with PortFast may also be connected to devices that legitimate send BPD

BPDU guard should be enabled on all PortFast-enabled ports to enhance Spanning Tree Protocol (STP) stability. When a switch port is configured with PortFast, it transitions immediately to the forwarding state, bypassing the usual STP listening and learning states. This is particularly useful for ports connected to end devices like computers or printers, where there should be no BPDUs (Bridge Protocol Data Units) received.

Enabling BPDU guard on these ports mitigates the risk of receiving unexpected BPDUs that could cause STP topology changes, leading to network loops or instability. If a BPDU is detected on a PortFast-enabled port, BPDU guard will shut the port down, thus maintaining the integrity of the spanning tree and preventing potential loops in the network.

On the other hand, enabling BPDU guard on VLAN trunks, access ports, or switch management interfaces does not address the primary concern of unexpected BPDUs in the context of PortFast ports. VLAN trunks are designed to carry BPDUs for all VLANs across connected switches and should not be configured with BPDU guard, as this would disrupt the transmission of these important control messages. Access ports not configured with PortFast may also be connected to devices that legitimate send BPD