Pass Your Cisco 350-401 Exam Easy!

That diagnosis is supported by a different symptom: A newly attached access switch advertises superior BPDUs and takes over root elections. Here the recorded observation is: an unauthorized unmanaged switch forms a loop through a supposedly trusted desk port. The applicable cause is: the access edge port lacked BPDU Guard and accepted unexpected BPDUs.

That diagnosis is supported by a different symptom: A loop persists after an unmanaged bridge joins two access ports because their inbound BPDUs were suppressed. Here the recorded observation is: an unauthorized unmanaged switch forms a loop through a supposedly trusted desk port. The applicable cause is: the access edge port lacked BPDU Guard and accepted unexpected BPDUs.

That diagnosis is supported by a different symptom: A blocked alternate port starts forwarding after BPDUs cease, creating a loop. Here the recorded observation is: an unauthorized unmanaged switch forms a loop through a supposedly trusted desk port. The applicable cause is: the access edge port lacked BPDU Guard and accepted unexpected BPDUs.

That control reduces a separate risk: Without loop guard the switch interprets missing BPDUs as permission to transition forwarding. For the described design, the recurring risk arises from: the access edge port lacked BPDU Guard and accepted unexpected BPDUs. The specific required safeguard is: keep PortFast/BPDU Guard scoped to endpoints and audit err-disable recovery policy.

That control reduces a separate risk: Per-instance STP forwarding state was confused with physical-link operability. For the described design, the recurring risk arises from: the access edge port lacked BPDU Guard and accepted unexpected BPDUs. The specific required safeguard is: keep PortFast/BPDU Guard scoped to endpoints and audit err-disable recovery policy.

That control reduces a separate risk: The distribution-facing designated link lacks root guard for the downstream boundary. For the described design, the recurring risk arises from: the access edge port lacked BPDU Guard and accepted unexpected BPDUs. The specific required safeguard is: keep PortFast/BPDU Guard scoped to endpoints and audit err-disable recovery policy.

Enabling supported loop guard on eligible non-designated point-to-point spanning-tree ports would not enable STP root guard on the appropriate designated downstream-facing interface.

Setting an appropriate lower bridge priority on the intended root switch for that STP instance/VLAN would not enable STP root guard on the appropriate designated downstream-facing interface.

Configuring an appropriate secondary root priority higher than primary but below ordinary access switches would not enable STP root guard on the appropriate designated downstream-facing interface.

This test measures a different behavior: Check `show spanning-tree vlan 100` root bridge ID and root port choices across the topology. It does not establish the target outcome. For the documented fault, the direct acceptance test is: present a superior BPDU and verify the port enters root-inconsistent state without replacing the desired root.

This test measures a different behavior: Suppress BPDUs in a lab and confirm the port enters loop-inconsistent rather than transitioning to designated forwarding. It does not establish the target outcome. For the documented fault, the direct acceptance test is: present a superior BPDU and verify the port enters root-inconsistent state without replacing the desired root.

This test measures a different behavior: Disable primary in a lab and inspect the next-lowest bridge ID selection. It does not establish the target outcome. For the documented fault, the direct acceptance test is: present a superior BPDU and verify the port enters root-inconsistent state without replacing the desired root.

That diagnosis is supported by a different symptom: An unintended access switch becomes root after the designed primary goes offline. Here the recorded observation is: a newly attached access switch advertises superior BPDUs and takes over root elections. The applicable cause is: the distribution-facing designated link lacks root guard for the downstream boundary.

That diagnosis is supported by a different symptom: A small access switch becomes VLAN100's spanning-tree root after a new switch is connected. Here the recorded observation is: a newly attached access switch advertises superior BPDUs and takes over root elections. The applicable cause is: the distribution-facing designated link lacks root guard for the downstream boundary.

That diagnosis is supported by a different symptom: A blocked alternate port starts forwarding after BPDUs cease, creating a loop. Here the recorded observation is: a newly attached access switch advertises superior BPDUs and takes over root elections. The applicable cause is: the distribution-facing designated link lacks root guard for the downstream boundary.

That control reduces a separate risk: No designated secondary root priority existed to guide the failover election. For the described design, the recurring risk arises from: the distribution-facing designated link lacks root guard for the downstream boundary. The specific required safeguard is: test STP root protection on every uncontrolled downstream switch-facing interface.

That control reduces a separate risk: Root priority policy was not established, so the lowest bridge ID won unexpectedly. For the described design, the recurring risk arises from: the distribution-facing designated link lacks root guard for the downstream boundary. The specific required safeguard is: test STP root protection on every uncontrolled downstream switch-facing interface.

That control reduces a separate risk: Without loop guard the switch interprets missing BPDUs as permission to transition forwarding. For the described design, the recurring risk arises from: the distribution-facing designated link lacks root guard for the downstream boundary. The specific required safeguard is: test STP root protection on every uncontrolled downstream switch-facing interface.

Enabling STP root guard on the appropriate designated downstream-facing interface would not enable supported loop guard on eligible non-designated point-to-point spanning-tree ports.

Removing the inappropriate BPDU Filter configuration so STP can receive and process unexpected BPDUs on the edge port would not enable supported loop guard on eligible non-designated point-to-point spanning-tree ports.

Setting an appropriate lower bridge priority on the intended root switch for that STP instance/VLAN would not enable supported loop guard on eligible non-designated point-to-point spanning-tree ports.

This test measures a different behavior: Check `show spanning-tree vlan 100` root bridge ID and root port choices across the topology. It does not establish the target outcome. For the documented fault, the direct acceptance test is: suppress BPDUs in a lab and confirm the port enters loop-inconsistent rather than transitioning to designated forwarding.

This test measures a different behavior: Inspect the interface BPDU filter state and verify received BPDUs are visible to STP during a controlled test. It does not establish the target outcome. For the documented fault, the direct acceptance test is: suppress BPDUs in a lab and confirm the port enters loop-inconsistent rather than transitioning to designated forwarding.

This test measures a different behavior: Present a superior BPDU and verify the port enters root-inconsistent state without replacing the desired root. It does not establish the target outcome. For the documented fault, the direct acceptance test is: suppress BPDUs in a lab and confirm the port enters loop-inconsistent rather than transitioning to designated forwarding.

That diagnosis is supported by a different symptom: A small access switch becomes VLAN100's spanning-tree root after a new switch is connected. Here the recorded observation is: a blocked alternate port starts forwarding after BPDUs cease, creating a loop. The applicable cause is: without loop guard the switch interprets missing BPDUs as permission to transition forwarding.

That diagnosis is supported by a different symptom: A newly attached access switch advertises superior BPDUs and takes over root elections. Here the recorded observation is: a blocked alternate port starts forwarding after BPDUs cease, creating a loop. The applicable cause is: without loop guard the switch interprets missing BPDUs as permission to transition forwarding.

That diagnosis is supported by a different symptom: A loop persists after an unmanaged bridge joins two access ports because their inbound BPDUs were suppressed. Here the recorded observation is: a blocked alternate port starts forwarding after BPDUs cease, creating a loop. The applicable cause is: without loop guard the switch interprets missing BPDUs as permission to transition forwarding.

That control reduces a separate risk: Root priority policy was not established, so the lowest bridge ID won unexpectedly. For the described design, the recurring risk arises from: without loop guard the switch interprets missing BPDUs as permission to transition forwarding. The specific required safeguard is: monitor inconsistent-port state and avoid applying loop guard as a substitute for root guard.

That control reduces a separate risk: The distribution-facing designated link lacks root guard for the downstream boundary. For the described design, the recurring risk arises from: without loop guard the switch interprets missing BPDUs as permission to transition forwarding. The specific required safeguard is: monitor inconsistent-port state and avoid applying loop guard as a substitute for root guard.

That control reduces a separate risk: BPDU Filter masked incoming STP BPDUs, preventing the switch from seeing the topology change. For the described design, the recurring risk arises from: without loop guard the switch interprets missing BPDUs as permission to transition forwarding. The specific required safeguard is: monitor inconsistent-port state and avoid applying loop guard as a substitute for root guard.

Setting an appropriate lower bridge priority on the intended root switch for that STP instance/VLAN would not align MST region name, revision and VLAN-to-instance mapping on the intended region members.

Mapping the VLAN groups into separate MST instances and tune root priorities per instance would not align MST region name, revision and VLAN-to-instance mapping on the intended region members.

Interpreting per-instance RSTP/MST port roles and forwarding states would not align MST region name, revision and VLAN-to-instance mapping on the intended region members.