VCP-DCV Configure and Manage vSphere Networking Practice Test 3 — 15 Questions

Question 1

Which THREE of the following are prerequisites for configuring LACP on a vSphere Distributed Switch? (Select exactly three.)

Accepted Answer

The vSphere Distributed Switch must be configured with enhanced LACP support.. Option A is correct because vSphere Distributed Switch LACP requires the switch to be configured with enhanced LACP support (available in vSphere 5.1 and later), which enables LAGs on the distributed switch and allows multiple uplinks to be aggregated. Option C is correct because the physical switch ports connected to the ESXi host uplinks must be configured for LACP in either active or passive mode so that LACP PDUs can be exchanged and the link aggregation can form. Option E is correct because the upstream physical switch must support the LACP protocol as defined in IEEE 802.3ad (Link Aggregation) for the LAG to be negotiated and function. Option B is incorrect because LACP uplinks in a LAG are not required to be in separate VLANs; VLAN separation is unrelated to LACP prerequisites and would not prevent loops. Option D is incorrect because LACP uplinks can connect to the same physical switch or to a stack/MLAG pair; connecting them to different physical switches is not a prerequisite, and without proper switch support it could even prevent the LAG from forming.

Answer

Each uplink must be in a separate VLAN to avoid loops.

Answer

The uplinks must be connected to different physical switches for redundancy.

Question 2

An ESXi host has two VMkernel interfaces as shown in the exhibit. The iSCSI targets are on the same subnet as vmk1 and support jumbo frames. The administrator reports that iSCSI sessions are experiencing high error rates and poor performance. What is most likely the cause?

Accepted Answer

The vDS port group for iSCSI does not have jumbo frames enabled (MTU 9000).. The iSCSI targets support jumbo frames, but the vDS port group for iSCSI likely has an MTU of 1500 instead of 9000. When the VMkernel interface (vmk1) sends large frames but the port group MTU is lower, fragmentation or drops occur, causing high error rates and poor performance. Enabling jumbo frames on the iSCSI VMkernel and the vDS port group is required for end-to-end jumbo frame support.

Answer

The management network (vmk0) is also using the vDS, causing traffic interference.

Answer

The iSCSI VMkernel port should not be bound to a vDS.

Answer

The iSCSI network (vmk1) is on a different subnet than the iSCSI targets.

Question 3

Based on the Healthcheck output for a distributed port (DVS Port 1) on dvs0, what can be concluded?

Accepted Answer

The physical switch is correctly configured for VLAN 100 and MTU 1500 on the uplinks connected to this host.. The Healthcheck output for DVS Port 1 on dvs0 shows that the physical switch is correctly configured for VLAN 100 and MTU 1500 on the uplinks connected to this host. This is indicated by the successful health check results for VLAN and MTU, meaning the physical switch ports are passing traffic with the expected VLAN tag and frame size. The other options are not supported by the output.

Answer

The uplinks vmnic0 and vmnic1 are operating at 10 Gbps.

Answer

The load balancing policy is set to 'Route based on IP hash'.

Answer

The port is experiencing high packet loss due to misconfiguration.

Question 4

A large financial organization has a vSphere cluster with 10 ESXi hosts (8.x) connected to a pair of Nexus 9000 switches via two 10G LACP link aggregation groups (LAGs) per host. Each host has a vSphere Distributed Switch (vDS 7.0.3) with two LAGs (LAG1: vmnic0, vmnic1; LAG2: vmnic2, vmnic3). The vDS has three port groups: Production (VLAN 100-200), DMZ (VLAN 300), and Storage (VLAN 400). The port groups use LACP with load balancing 'Route based on IP hash'. Recently, the network team changed the physical switch port channels from mode 'active' to 'passive' on the downstream ports connected to host #3, without informing the virtualization team. Within hours, VMs on host #3 experience intermittent connectivity; some can communicate but others cannot, and vMotion between host #3 and other hosts fails with a network unreachable error. iSCSI storage traffic from host #3 is also unstable. The administrator verifies that the vDS LACP configuration on host #3 still expects 'active' mode. Which of the following actions is the most effective to restore full functionality while maintaining LACP?

Accepted Answer

Remove and recreate the LAGs on host #3's vDS after verifying the physical switch's LACP configuration.. The root cause is a mismatch between the vDS LACP mode (active) and the physical switch's LACP mode (passive). Simply recreating the LAGs after verifying the switch configuration ensures both sides agree on the LACP mode, restoring proper negotiation and traffic flow. This maintains the existing LACP-based load balancing and avoids disrupting the rest of the cluster.

Answer

Change the LACP mode on host #3's vDS from 'active' to 'passive' for both LAGs.

Answer

Disable LACP on host #3's vDS and use static EtherChannel instead.

Answer

Replace the vDS with multiple standard switches and use active/standby failover.

Question 5

A vSphere administrator needs to provide network connectivity to a set of VMs that must be isolated from all other traffic on the physical network. The VMs are on the same ESXi host and require maximum throughput between them. Which vSphere networking solution should the administrator use?

Accepted Answer

Create a standard switch with an internal-only port group (no uplinks). A standard switch with no uplinks creates an internal-only network that provides isolation and maximum throughput as traffic stays within the ESXi host memory. Option A requires uplinks and VLAN configuration, allowing potential traffic exposure. Option B requires physical switch support for private VLANs and still uses uplinks. Option C incorrectly uses a VMkernel NIC, which is for management traffic, not VM data.

Answer

Create a distributed switch with a private VLAN

Answer

Create a standard switch with a VLAN-backed port group

Answer

Create a standard switch with a VMkernel NIC for inter-VM communication

Question 6

An organization uses a VDS with 4 hosts. They want to use Network I/O Control (NIOC) to prioritize vMotion traffic over management traffic. After configuring NIOC, the administrator notices that vMotion performance is not improved. What could be the cause?

Accepted Answer

The vMotion VMkernel adapter is not assigned to the correct network resource pool. Network I/O Control (NIOC) on a vSphere Distributed Switch prioritizes traffic based on network resource pools. If the vMotion VMkernel adapter is not assigned to the correct network resource pool (e.g., the vMotion pool with higher shares), NIOC cannot prioritize its traffic, so vMotion performance is not improved.

Answer

The physical uplinks are oversubscribed

Answer

The vMotion traffic is not marked with the appropriate CoS tag

Answer

NIOC is not enabled on the VDS

Question 7

A company deploys a VDS with multiple uplinks and uses Route based on originating virtual port for load balancing. The network team reports that traffic from VMs on the same host is not balanced across uplinks. The administrator verifies that the physical switch ports are all in the same port-channel. What could be the cause?

Accepted Answer

The uplinks are configured in active/standby mode. With 'Route based on originating virtual port', each VM's traffic is pinned to a single uplink based on its virtual port ID. If the uplinks are in active/standby mode, only the active uplink carries traffic — the standby is unused — so traffic from VMs on the same host is not balanced across uplinks. This matches the symptom exactly.

Answer

The load balancing algorithm is not supported by the physical switch

Answer

The number of VMs is less than the number of uplinks

Answer

The teaming policy uses an explicit failover order

Question 8

An administrator needs to create a distributed port group on a vSphere Distributed Switch (VDS). Which two configuration settings must be specified during creation? (Choose two.)

Accepted Answer

VLAN ID. A VLAN ID must be specified to define the VLAN membership for the distributed port group, ensuring proper network segmentation and traffic isolation. The port group name is required as a unique identifier for administrative management and reference within the vSphere environment.

Answer

Uplink teaming policy

Answer

Number of ports

Answer

Traffic shaping policy

Question 9

A virtual machine connected to the 'VM Network' port group is unable to obtain an IP address from the DHCP server located on the same subnet (192.168.1.0/24). The DHCP server is connected to the physical switch which is configured as an access port for VLAN 100. What is the most likely cause of the issue?

Accepted Answer

The port group should use a different VLAN ID.. The virtual machine is connected to the default 'VM Network' port group, which has VLAN ID 0 (no VLAN tagging), sending untagged traffic. The DHCP server is connected to a physical switch port configured as an access port for VLAN 100, placing it in VLAN 100. Because the VM and the DHCP server are on different VLANs, they cannot communicate at Layer 2, preventing DHCP discovery broadcasts from reaching the server. The most likely cause is that the port group should use a different VLAN ID (VLAN 100) to match the DHCP server's VLAN. Changing the port group to VLAN 100 will tag the traffic, requiring a trunk on the physical uplink, but the root cause is the VLAN mismatch, not solely the uplink configuration.

Answer

The physical uplink vmnic0 is not configured as a trunk on the physical switch.

Answer

The standard switch has MTU of 1500 but DHCP uses 1500.

Answer

The DHCP server is on a different VLAN.

Answer

The VMkernel port vmk0 has an IP address in the same subnet but is not required for DHCP.

Question 10

A company runs a vSphere 7 cluster with 4 ESXi hosts, each connected to a single vSphere Distributed Switch (VDS) with two 10GbE uplinks. The environment hosts 100 production VMs and uses vSphere Replication for disaster recovery to a remote site. Network I/O Control (NIOC) is enabled on the VDS with the following shares: vSphere Replication (System Traffic) = 100, Virtual Machine Traffic = 50. During the scheduled replication window (every 2 hours), users report significant VM performance degradation. The administrator observes that during replication, the VMkernel interfaces handling replication consume 95% of the available uplink bandwidth. The goal is to guarantee at least 6 Gbps of bandwidth for VM traffic on each host while still allowing replication to occur. Which action should the administrator take?

Accepted Answer

Create a network resource pool for VM traffic on the VDS and assign a reservation of 6 Gbps.. Creating a network resource pool for VM traffic and assigning a reservation of 6 Gbps guarantees that VM traffic gets at least that amount of bandwidth, regardless of replication demands. This is the proper use of NIOC resource pools. Option B (increasing shares) only affects priority, not guarantees. Option C (limiting replication) could help but does not guarantee VM bandwidth and may still allow replication to burst if the limit is not set appropriately. Option D (adding uplinks) is expensive and may not directly address the guarantee requirement.

Answer

Increase the shares for Virtual Machine traffic to 200.

Answer

Increase the number of uplinks to four per host.

Answer

Set a hard limit of 4 Gbps on vSphere Replication traffic.

Question 11

Refer to the exhibit. The ESXi host has three VMkernel interfaces. A vMotion operation fails with a routing error. Which is the most likely cause?

Accepted Answer

The vMotion VMkernel interface is on vmk2, but no route exists for the vMotion destination network.

Answer

The vMotion VMkernel interface uses DHCP.

Answer

The vMotion VMkernel interface is on vmk1, but the default gateway points to vmk0.

Answer

The vMotion VMkernel interface is on vmk0, but the gateway is incorrect.

Question 12

Refer to the exhibit. An administrator notices that virtual machines on the Production port group are unable to communicate with hosts on VLAN 200. The Management and Storage port groups work fine. What is the most likely cause?

Accepted Answer

The MTU setting on the DSwitch (9000) is incompatible with the physical network for VLAN 200.. The exhibit shows the DSwitch configured with an MTU of 9000 (jumbo frames), while the physical network for VLAN 200 only supports the standard 1500 MTU. When the Production port group's traffic traverses the uplink, jumbo frames are dropped by the physical switch, breaking connectivity. Management and Storage port groups work because their traffic either uses smaller frames or does not traverse the mismatched path.

Answer

The uplinks for DSwitch are not properly configured for VLAN 200.

Answer

The Production port group is not attached to any uplink.

Answer

There is a VLAN ID mismatch between the virtual switch and physical switch for VLAN 200.

Question 13

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?

Accepted Answer

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.

Answer

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

Answer

The DVS version 7.0.0 does not support beacon probing.

Answer

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

Question 14

Refer to the exhibit. An administrator checks the status of a distributed switch port and sees no errors or drops. However, virtual machines on this port cannot communicate with the default gateway at 192.168.200.1. What is the most likely cause?

Accepted Answer

The port is configured with Allowed VLANs 100, 200, 300, which is a trunk configuration, but the virtual machine expects an access port on VLAN 200.. The exhibit shows the port has Allowed VLANs: 100, 200, 300. This is unusual because a port should typically be assigned to a single VLAN (access port) or carry multiple VLANs (trunk port). If the port is set to allow multiple VLANs but the virtual machine expects a specific VLAN, packets may be misconfigured. However, the most likely cause is that the port is configured as a trunk port (allows multiple VLANs) when it should be an access port for VLAN 200. This can cause the virtual machine to receive traffic from other VLANs or not tag its own traffic correctly.

Answer

The port has no allowed MAC addresses, which may cause filtering.

Answer

The MTU is set to 1500, which is standard and should work fine.

Answer

The link speed is 10 Gbps, which is sufficient.

Question 15

Refer to the exhibit. An engineer tries to ping the DNS server 10.0.0.1 from the management interface vmk0 but gets 'Network is unreachable'. What is the most likely cause?

Accepted Answer

The vmk0 interface does not have a default gateway configured; the default gateway is on vmk1.. 'Network is unreachable' is an ICMP error generated locally when the host has no route to the destination network. If vmk0 has no default gateway and the DNS server 10.0.0.1 is off-subnet, ESXi cannot route the packet and returns this error immediately. Configuring the default gateway on vmk0 (or ensuring the correct TCP/IP stack has the gateway) resolves it.

Answer

The DNS server 10.0.0.1 is down.

Answer

The MTU of 1500 is too small for DNS traffic.

Answer

The DNS server IP address is misconfigured.