RSTP provides different functions in different scenarios. Which of the following statements is FALSE?

Question

Options

• AAfter TC-BPDU attack defense function is enabled, you can set the number of times the switch processes TC BPDUs within a certain period
• BThe role of the designated port is not enabled with root protection cannot be changed.
• CIf an edge port on the switch enabled with BPDU protection receives an RSTP BPDU, the switch sets the edge port as a non-edge-port and triggers STP calculation
• DWhen the designated port enabled with root protection receives optimal RST BPDUs, the port enters the Discarding state and does not forward packets. If the port does not receive optimal RST BPDUs within a certain period of time, the port will automatically restore to the Forwarding state

• A
  14% (3)
• B
  76% (16)
• C
  5% (1)
• D
  5% (1)

Explanation

Option B is false because root protection does not permanently lock the role of a designated port. When a designated port enabled with root protection receives a superior BPDU that would cause it to become a root port, the port enters a root-inconsistent (discarding) state - meaning the port role can in fact change. Option D accurately describes this mechanism: the port enters the Discarding state upon receiving superior BPDUs, then automatically restores to Forwarding once the superior BPDUs stop, making D a true statement. Option A is true: TC-BPDU attack defense lets you configure a threshold for how many TC BPDUs are processed per interval, preventing MAC address table flooding. Option C is true: a BPDU-protection-enabled edge port that receives a BPDU is reclassified as a non-edge port, triggering an STP recalculation to ensure the network converges correctly.

Memory tip: Root protection "guards the root bridge" by blocking ports that try to compete with it, but blocking is temporary and role-dependent - it does not freeze roles permanently, which is what makes B false.

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