Hi,
To create an alarm for host network utilization, select the vCenter instance by connecting to the vSphere client. Navigate to Alarms tab and right click and select new Alarm. For Alarm Type to Monitor select Host and in the Triggers tab select Host Network Usage (KBps) you can select Warning for 80% and configure the action accordingly.
-Arun
http://highoncloud.blogspot.in/
About VMware Virtualization on NetApp