The following are some important features of VEM:
- It is a virtual line card
- It is embedded in the vSphere host (hypervisor)
- It provides each VM with dedicated switch ports
- It is the switch in every host
Here, we run the ESXi package manager to show the VIB file used to implement the VEM. If you list the processes, you will also see the VEM data path agent (vemdpa) that communicates with the VSM (running in the user mode).
Finally, the hypervisor driver (running in the kernel mode) performs packet switching.
vCenter can operate without too much regard for the VEM. Typically, the only reason to go there (via SSH) is for troubleshooting purposes.
The esxupdate utility is no longer supported, but we can use it here to illustrate a point.