VCP550 · Question #41
A vSphere administrator assigns VLAN 3389 to the Production port group on the VCP_DCV_Example vSphere Distributed Switch. After the change, users report a loss of connectivity to their applications. F
The correct answer is A. The physical switch ports used by the vmnics have not been configured with 802.1Q.. Assigning a VLAN ID to a distributed port group requires the connected physical switch ports to be configured as 802.1Q trunks; without this, the tagged frames are dropped and connectivity fails immediately.
Question
A vSphere administrator assigns VLAN 3389 to the Production port group on the VCP_DCV_Example vSphere Distributed Switch. After the change, users report a loss of connectivity to their applications. Further analysis provides the following data:
- The cluster has not had a ESXi host failure.
- Application functioned normally prior to the change.
- The loss of connectivity occurred immediately following the change.
Which condition would cause this loss of connectivity?
Exhibit
Options
- AThe physical switch ports used by the vmnics have not been configured with 802.1Q.
- BMaintenance Mode was initiated on one of the hosts in the cluster. Connectivity will resume after the
- CAll uplinks were removed from the VCP_DCV_Example switch and added to another virtual switch.
- DA load balancing setting on the port group conflicts with the load balancing setting of the switch.
How the community answered
(22 responses)- A59% (13)
- B5% (1)
- C23% (5)
- D14% (3)
Why each option
Assigning a VLAN ID to a distributed port group requires the connected physical switch ports to be configured as 802.1Q trunks; without this, the tagged frames are dropped and connectivity fails immediately.
When VLAN 3389 is assigned to a distributed port group, the ESXi host tags all egress traffic with that VLAN ID using 802.1Q encapsulation. If the upstream physical switch ports connected to the vmnics are not configured as 802.1Q trunk ports that permit VLAN 3389, the tagged frames are discarded, which directly explains the immediate and complete loss of connectivity observed the moment the change was applied.
The question explicitly states no ESXi host failure occurred and makes no mention of Maintenance Mode being initiated, so this scenario cannot account for the connectivity loss.
Removing all uplinks from the virtual switch would have caused connectivity loss before the VLAN change was made, not as a direct consequence of assigning a new VLAN ID.
A load balancing setting conflict affects how traffic is distributed across uplinks but does not cause total connectivity loss tied specifically to assigning a VLAN ID to a port group.
Concept tested: 802.1Q VLAN trunking required for vSphere Distributed Switch port groups
Source: https://docs.vmware.com/en/VMware-vSphere/8.0/vsphere-networking/GUID-7225A28C-DAAB-4E90-95A0-62CC4F9B84D3.html
Topics
Community Discussion
No community discussion yet for this question.