Network counters at the ESXi level
vCenter provides three additional counters at the host level. It can track Packet receive errors, Packet transmit errors, and Unknown protocol frames. The counters are provided at either the host level or vmnic level. They are not provided at the switch or port group level. This means you cannot gauge the performance at the port group level or switch level easily using vCenter.
ESXi Network counters
Just like vCenter, vRealize Operations also does not provide the counters at the standard switch or port group level. This means you cannot aggregate or analyze the data from these network objects' point of view. This is one reason why I prefer to use Distributed Switch. It simply has a much richer monitoring capability.
Usage, Data Received Rate, and Data Transmit Rate are all available at the host level and at the individual NIC level. I'm showing just vmnic3 and the host in this screenshot:
You should expect the value for packets dropped and unknown packet frames...
