The operational state of a VSAN on this port. If the port
is in trunking mode, it is possible that the port state
may be 'down(2)' only in some VSANs. If this port is down
in this VSAN only then port state shown by 'ifOperStatus'
may not be 'down(2)', but this object will show
'down(2)'.
The 'fcTrunkIfOperStatusCause' object shows the reason
for port being 'down(2)'.