Question 336 of 521
Configure and Manage vSphere NetworkinghardMultiple ChoiceObjective-mapped

Beacon Probing Requires Three Uplinks

This VCP-DCV practice question tests your understanding of configure and manage vsphere networking. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

Exhibit

net-dvs -l | grep -A 20 "DVS name: DSwitch"
DVS name: DSwitch
  vcenter: vcenter.lab.local
  uuid: 50 1a 2b 3c 4d 5e 6f 70 80 90 a0 b0 c0 d0 e0 f0
  numPorts: 256
  switchType: distributed
  version: 7.0.0
  uplinkPorts: 4
  host: esxi1.lab.local (vmnic1, vmnic2)
  host: esxi2.lab.local (vmnic1, vmnic2)
  host: esxi3.lab.local (vmnic1, vmnic2)
  host: esxi4.lab.local (vmnic1, vmnic2)

  Port group: Production
    VLAN: 200
    Used by: VM1, VM2, VM3
    Active uplinks: vmnic1, vmnic2
    Standby uplinks: (none)
    Load balancing: Route based on IP hash
    Network failure detection: Beacon probing only

Refer to the exhibit. An administrator configured beacon probing for network failure detection on the Production port group. However, virtual machines are experiencing intermittent connectivity. What is the most likely reason?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Exhibit

net-dvs -l | grep -A 20 "DVS name: DSwitch"
DVS name: DSwitch
  vcenter: vcenter.lab.local
  uuid: 50 1a 2b 3c 4d 5e 6f 70 80 90 a0 b0 c0 d0 e0 f0
  numPorts: 256
  switchType: distributed
  version: 7.0.0
  uplinkPorts: 4
  host: esxi1.lab.local (vmnic1, vmnic2)
  host: esxi2.lab.local (vmnic1, vmnic2)
  host: esxi3.lab.local (vmnic1, vmnic2)
  host: esxi4.lab.local (vmnic1, vmnic2)

  Port group: Production
    VLAN: 200
    Used by: VM1, VM2, VM3
    Active uplinks: vmnic1, vmnic2
    Standby uplinks: (none)
    Load balancing: Route based on IP hash
    Network failure detection: Beacon probing only

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

There are only two uplinks, and beacon probing requires at least three uplinks.

Beacon probing requires at least three uplinks to function correctly. The exhibit shows only two uplinks (vmnic1 and vmnic2) are active. With two uplinks, beacon probing cannot reliably detect failures because there are not enough beacons to determine which link is down. This can cause false positives and connectivity issues.

Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • There are only two uplinks, and beacon probing requires at least three uplinks.

    Why this is correct

    Beacon probing needs three or more uplinks to properly detect failures. With two uplinks, it can cause flapping.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Access ports place end devices into a single VLAN.

  • The VLAN ID 200 is not allowed on the physical switch trunks.

    Why it's wrong here

    The exhibit does not indicate VLAN tagging issues; the problem is related to beacon probing.

  • The DVS version 7.0.0 does not support beacon probing.

    Why it's wrong here

    Beacon probing is supported in vSphere 7.0.

  • The load balancing policy is set to Route based on IP hash, which is incompatible with beacon probing.

    Why it's wrong here

    IP hash is compatible with beacon probing; they are independent settings.

Common exam traps

Common exam trap: an active trunk can still block the VLAN you need

A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.

Detailed technical explanation

How to think about this question

VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.

KKey Concepts to Remember

  • Access ports place end devices into a single VLAN.
  • Trunk ports carry multiple VLANs between switches.
  • Allowed VLAN lists decide which VLANs can cross a trunk.
  • Native VLAN mismatch can create confusing symptoms.

TExam Day Tips

  • Use show vlan brief to verify access VLANs.
  • Use show interfaces trunk to verify trunk state and allowed VLANs.
  • Do not treat every same-VLAN issue as a routing problem.

Key takeaway

A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.

Real-world example

How this comes up in practice

A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.

What to study next

Got this wrong? Here's your next step.

Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related VCP-DCV questions on switching, trunking, and access-port configuration.

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FAQ

Questions learners often ask

What does this VCP-DCV question test?

Configure and Manage vSphere Networking — This question tests Configure and Manage vSphere Networking — Access ports place end devices into a single VLAN..

What is the correct answer to this question?

The correct answer is: There are only two uplinks, and beacon probing requires at least three uplinks. — Beacon probing requires at least three uplinks to function correctly. The exhibit shows only two uplinks (vmnic1 and vmnic2) are active. With two uplinks, beacon probing cannot reliably detect failures because there are not enough beacons to determine which link is down. This can cause false positives and connectivity issues.

What should I do if I get this VCP-DCV question wrong?

Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related VCP-DCV questions on switching, trunking, and access-port configuration.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Access ports place end devices into a single VLAN.

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Last reviewed: Jul 4, 2026

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This VCP-DCV practice question is part of Courseiva's free VMware certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the VCP-DCV exam.