You can add system VLANs as an optional parameter in a port profile. When you use the system VLAN parameter in a port profile, it helps the port profile to act as a special system port profile that is included in the N1KV opaque data. Interfaces that use this type of port profile, along with the members of one of the system VLANs, by default get enabled and forwarded. As a ripple effect, if the VEM does not have communication with the VSM, it still communicates when the ESXi host starts. This enables the use of critical host functions if the ESXi host starts, but it is unable to communicate with the VSM.

As a Cisco best practice, both the control and packet VLANs must be defined as system VLANs. Without this, they will not be included in the opaque data and therefore, the VEM will be unable to communicate with the VSM.