VCP-DCV Configure and Manage vSphere Networking Practice Question
A vSphere administrator is configuring Network I/O Control (NIOC) on a vSphere Distributed Switch. The administrator creates a new network resource pool named 'High Priority' and assigns it a shares value of 'High'. The administrator then assigns a VM's vNIC to a port group that uses this resource pool. However, the VM's traffic is not receiving the expected prioritization during congestion. What is a possible reason for this?
⚠ Common exam trap
The trap here is assuming that configuring shares alone is sufficient, but NIOC must be explicitly enabled on the distributed switch for those shares to be enforced.
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
✓
NIOC is not enabled on the vSphere Distributed Switch.
NIOC must be enabled on the vSphere Distributed Switch for network resource pools and shares to function. If NIOC is disabled, the shares values are ignored, and all traffic is treated equally. The other options are either unrelated to NIOC (VLAN, physical switch QoS) or misconceptions (reservations are not required for shares). Therefore, the administrator should verify that NIOC is enabled on the switch.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The VM's vNIC is not configured with a reservation.
Why it's wrong here
NIOC shares are used to allocate bandwidth during contention based on relative shares, not absolute reservations. A reservation guarantees a minimum bandwidth but is not required for shares to take effect. The lack of a reservation does not prevent the shares from providing prioritization; shares are relative and only matter when there is contention. Therefore, this is not the reason for the lack of prioritization.
- ✗
The physical switch is not configured to trust CoS/DSCP tags.
Why it's wrong here
NIOC operates at the hypervisor level and does not rely on physical switch trust of CoS/DSCP tags for its prioritization. While physical switch QoS can complement NIOC, NIOC itself enforces shares and limits within the ESXi host. The lack of physical switch trust would not prevent NIOC from prioritizing traffic on the host; it would only affect end-to-end QoS across the physical network.
- ✗
The port group is not assigned to a VLAN.
Why it's wrong here
VLAN assignment is independent of NIOC prioritization. A port group without a VLAN can still have NIOC shares applied to its traffic. The VLAN tag affects Layer 2 segmentation, not the bandwidth allocation provided by NIOC. Therefore, the absence of a VLAN is not the cause of the missing prioritization.
- ✓
NIOC is not enabled on the vSphere Distributed Switch.
Why this is correct
NIOC must be enabled on the vSphere Distributed Switch for network resource pools and shares to take effect. If NIOC is disabled, all traffic is treated equally, and no prioritization occurs regardless of the shares configured. The administrator must enable NIOC on the switch before resource pools can be used to prioritize traffic.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official VMware exam blueprint
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