The important network metrics to watch for are as follows:

Network Interface\Current Bandwidth - If this changes, your line speed has changed.  That means you've had a cable event, or a switch event.  Something is amiss.  We don't care what the value is, so much as we care its static.

Network Interface\Packets Outbound Discarded - We want this to be 0.  If you see values here, you are dropping/discarding packets that did not have errors, and had no line errors.  This is almost always a buffer overrun occurring.

Network Interface \Packets Outbound Errors - This is simply the number of packets we could not send because they were not 'healthy' or some line issue occurred.  Basically a fail to xmit.

Network Interface\Packets Received Discarded - See above

Network Interface\Packets Received Errors - See above as well.

Network Interface\Output Queue Length - >2 means there is a network delay or bottleneck somewhere in LAN/WAN territory.  This isn't the OS, this is the wire and beyond.  Network Queuing is where we are actively waiting, as an Operating System, on the wire to show available to transmit.  This is not a good condition to be in.