in vcenter there are at least three events, any one of which could be triggered, they all start with Network... and can be viewed at the vCenter level (top in left pane of vsphere client) in the Alarms tab
if you click the Alarms display, bottom left of the vsphere client window the bottom part of the window will switch to the Alarms and should display the alert.
the active one should be display when the nic is disconnected.
editing the Alarm definition at the vCenter level allows you to choose from a number of actions like sending email.
