The value of tMirrorLiSourceNatEthertype specifies
the ethertype of the ethernet encapsulation used for the NAT
subscribers associated with this mirror source that have
an intercept identifier.
If no intercept identifier is available for a NAT subscriber,
the value of tMirrorLiSourceNatEthertype is ignored.
The value of tMirrorLiSourceNatEthertype is only useful
if the value of tMirrorDestinationEncapsulation of the corresponding
mirror destination is equal to 'ether'.