The value of tMirrorLiSourceNatDestMacAddr specifies the Destination MAC
Address field of the of the ethernet encapsulation used for the NAT
subscribers associated with this mirror source.
The value of tMirrorLiSourceNatDestMacAddr is only useful
if the value of tMirrorDestinationEncapsulation of the corresponding
mirror destination is equal to 'ether'.
If no value for tMirrorLiSourceNatDestMacAddr is specified, the value
of TIMETRA-CHASSIS-MIB::tmnxChassisBaseMacAddress is used.