CompTIA N10-009 Practice Test 25

Question 240

A network specialist investigates this evidence: Hosts on VLAN 55 can reach each other but no gateway responds from their managed Layer 3 switch. Which underlying condition BEST explains the observed failure or requirement?

The physical links have not been bundled into an agreed aggregation.
The access port is in the wrong VLAN.
Bridge priorities do not designate the intended root.
The VLAN lacks an active switch virtual interface with the correct address.

Explanation

Correct Answer

The VLAN lacks an active switch virtual interface with the correct address. An SVI provides a Layer 3 interface for a switch VLAN.

Incorrect Answers

LACP forms a logical link only when partner identities and member parameters agree. The missing change involves the VLAN lacks an active switch virtual interface with the correct address.

An untagged host inherits its access-port VLAN. The missing change involves the VLAN lacks an active switch virtual interface with the correct address.

Bridge priorities do not designate the intended root. That does not establish correct switch VLAN and trunk classification.

Question 241

A network team observes: Two switch uplinks are connected in parallel but only one forwards and the other is blocked by spanning tree. What is the MOST appropriate corrective action or technical decision?

Configure compatible LACP port channels on both ends.
Create and enable an SVI for VLAN 55 with gateway IP and routing enabled.
Assign the port to the approved data VLAN and retain separate voice configuration.
Set deterministic root bridge priority on appropriate distribution switches.

Explanation

Correct Answer

LACP combines matched links into a logical forwarding interface. The physical links have not been bundled into an agreed aggregation.

Incorrect Answers

Creating and enabling an SVI for VLAN 55 with gateway IP and routing enabled would not configure compatible LACP port channels on both ends.

Assigning the port to the approved data VLAN and retaining separate voice configuration would not configure compatible LACP port channels on both ends.

Setting deterministic root bridge priority on appropriate distribution switches would not configure compatible LACP port channels on both ends.

Question 242

A network team addresses this situation: Two switch uplinks are connected in parallel but only one forwards and the other is blocked by spanning tree. After the corrective action, which test or result BEST verifies that the problem is resolved?

Inspect elected root ID and path costs after convergence.
Verify bundled-member state and traffic redistribution on link failure.
Check port VLAN and renew an office DHCP lease.
Check SVI operational state and ping it from VLAN clients.

Explanation

Correct Answer

Verify bundled-member state and traffic redistribution on link failure.

Incorrect Answers

Expected root election validates the priority plan. It does not verify bundled-member state and traffic redistribution on link failure.

Correct VLAN and subnet address confirm access membership. It does not verify bundled-member state and traffic redistribution on link failure.

VLAN membership and 802.1Q tagging determine which Layer 2 broadcast domain carries each frame. It does not verify bundled-member state and traffic redistribution on link failure.

Question 243

A network specialist investigates this evidence: Two switch uplinks are connected in parallel but only one forwards and the other is blocked by spanning tree. Which underlying condition BEST explains the observed failure or requirement?

The VLAN lacks an active switch virtual interface with the correct address.
The access port is in the wrong VLAN.
The physical links have not been bundled into an agreed aggregation.
Bridge priorities do not designate the intended root.

Explanation

Correct Answer

The physical links have not been bundled into an agreed aggregation. LACP combines matched links into a logical forwarding interface.

Incorrect Answers

An SVI provides a Layer 3 interface for a switch VLAN. That does not establish a correctly negotiated and collecting/distributing link aggregation.

An untagged host inherits its access-port VLAN. That does not establish a correctly negotiated and collecting/distributing link aggregation.

Bridge priorities do not designate the intended root. That does not establish a correctly negotiated and collecting/distributing link aggregation.

Question 244

A network team observes: A 1Gbps access uplink exhibits late collisions and very low throughput after one side is forced half-duplex. What is the MOST appropriate corrective action or technical decision?

Align supported MTUs on every hop or reduce workload frame size to the path limit.
Set deterministic root bridge priority on appropriate distribution switches.
Assign the port to the approved data VLAN and retain separate voice configuration.
Restore compatible auto-negotiation or matching supported duplex settings.

Explanation

Correct Answer

Duplex mismatch produces collisions and degraded throughput. Interface duplex settings disagree across the ethernet link.

Incorrect Answers

Aligning supported MTUs on every hop or reduce workload frame size to the path limit would not restore compatible auto-negotiation or matching supported duplex settings.

Setting deterministic root bridge priority on appropriate distribution switches would not restore compatible auto-negotiation or matching supported duplex settings.

Assigning the port to the approved data VLAN and retaining separate voice configuration would not restore compatible auto-negotiation or matching supported duplex settings.

Question 245

A network team addresses this situation: A 1Gbps access uplink exhibits late collisions and very low throughput after one side is forced half-duplex. After the corrective action, which test or result BEST verifies that the problem is resolved?

Check both negotiated modes and error counters under sustained traffic.
Probe accepted frame size and verify jumbo transfers.
Inspect elected root ID and path costs after convergence.
Verify bundled-member state and traffic redistribution on link failure.

Explanation

Correct Answer

Matching duplex and reduced collisions confirm remediation.

Incorrect Answers

Frame and path MTU limits can drop oversized packets without changing higher-layer routes.

Expected root election validates the priority plan. It does not check both negotiated modes and error counters under sustained traffic.

Verify bundled-member state and traffic redistribution on link failure. It does not check both negotiated modes and error counters under sustained traffic.

Question 246

A network specialist investigates this evidence: A 1Gbps access uplink exhibits late collisions and very low throughput after one side is forced half-duplex. Which underlying condition BEST explains the observed failure or requirement?

The path MTU is inconsistent for jumbo frames.
Interface duplex settings disagree across the Ethernet link.
The physical links have not been bundled into an agreed aggregation.
Bridge priorities do not designate the intended root.

Explanation

Correct Answer

Interface duplex settings disagree across the Ethernet link. Duplex mismatch produces collisions and degraded throughput.

Incorrect Answers

Frame and path MTU limits can drop oversized packets without changing higher-layer routes. The missing change involves interface duplex settings disagree across the Ethernet link.

LACP forms a logical link only when partner identities and member parameters agree. The missing change involves interface duplex settings disagree across the Ethernet link.

Bridge priorities do not designate the intended root. That does not establish interface duplex settings disagree across the Ethernet link.

Question 247

A network team observes: A temporary redundant patch cable creates a storm and flapping MAC entries across an access VLAN. What is the MOST appropriate corrective action or technical decision?

Permit VLAN 40 on the correct 802.1Q trunk endpoints.
Assign the port to the approved data VLAN and retain separate voice configuration.
Restore spanning-tree protection and remove the accidental redundant loop.
Configure compatible LACP port channels on both ends.

Explanation

Correct Answer

STP blocks redundant paths that would form persistent bridging cycles. A layer 2 loop exists without effective stp control.

Incorrect Answers

Permitting VLAN 40 on the correct 802.1Q trunk endpoints would not restore spanning-tree protection and remove the accidental redundant loop.

Assigning the port to the approved data VLAN and retaining separate voice configuration would not restore spanning-tree protection and remove the accidental redundant loop.

Configuring compatible LACP port channels on both ends would not restore spanning-tree protection and remove the accidental redundant loop.

Question 248

A network team addresses this situation: A temporary redundant patch cable creates a storm and flapping MAC entries across an access VLAN. After the corrective action, which test or result BEST verifies that the problem is resolved?

Capture VLAN 40-tagged frames and test same-VLAN host reachability.
Verify bundled-member state and traffic redistribution on link failure.
Inspect operational trunk state and validate tagged VLAN traffic.
Check root and blocked-port roles while monitoring broadcast rate.

Explanation

Correct Answer

Stable topology and counters demonstrate loop suppression.

Incorrect Answers

That test concerns 802.1q tagged trunk rather than the specific reported condition. Stable topology and counters demonstrate loop suppression.

Verify bundled-member state and traffic redistribution on link failure. It does not check root and blocked-port roles while monitoring broadcast rate.

VLAN membership and 802.1Q tagging determine which Layer 2 broadcast domain carries each frame. It does not check root and blocked-port roles while monitoring broadcast rate.

Question 249

A network specialist investigates this evidence: A temporary redundant patch cable creates a storm and flapping MAC entries across an access VLAN. Which underlying condition BEST explains the observed failure or requirement?

A Layer 2 loop exists without effective STP control.
The access port is in the wrong VLAN.
The physical links have not been bundled into an agreed aggregation.
Port-mode mismatch drops or misclassifies tagged traffic.

Explanation

Correct Answer

A Layer 2 loop exists without effective STP control. STP blocks redundant paths that would form persistent bridging cycles.

Incorrect Answers

An untagged host inherits its access-port VLAN. That does not establish a Layer 2 loop exists without effective STP control.

LACP forms a logical link only when partner identities and member parameters agree. The missing change involves a Layer 2 loop exists without effective STP control.

Port-mode mismatch drops or misclassifies tagged traffic. That does not establish a Layer 2 loop exists without effective STP control.

Question 250

A network team observes: A low-capacity edge switch becomes STP root after replacement and traffic takes undesirable uplinks. What is the MOST appropriate corrective action or technical decision?

Configure compatible LACP port channels on both ends.
Set deterministic root bridge priority on appropriate distribution switches.
Remove the unauthorized bridge, confirm edge role, and follow controlled reenable procedure.
Disable unused access ports and configure supported port security for required active jacks.

Explanation

Correct Answer

STP selects the root based on bridge identifier priority. Bridge priorities do not designate the intended root.

Incorrect Answers

Configuring compatible LACP port channels on both ends would not set deterministic root bridge priority on appropriate distribution switches.

Removing the unauthorized bridge, confirm edge role, and follow controlled reenable procedure would not set deterministic root bridge priority on appropriate distribution switches.

Disable unused access ports and configure supported port security for required active jacks would not set deterministic root bridge priority on appropriate distribution switches.

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Question 240

Explanation

Correct Answer

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Question 241

Explanation

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Question 242

Explanation

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Question 243

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Question 244

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Question 245

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Question 246

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Question 247

Explanation

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Question 248

Explanation

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Question 249

Explanation

Correct Answer

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Question 250

Explanation

Correct Answer

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CompTIA Network+ (N10-009) Practice Tests