The desired stack unit position. Note that setting this MIB
object will take effect only after setting the rlPhdStackReorder MIB
object below. After setting this MIB object and until a further change
of at least one instance of the rlPhdStackOrderDesiredUnitPosition object,
the values of the rlPhdStackOrderCurrentUnitPosition objectinstance and
the corresponding rlPhdStackOrderDesiredUnitPosition object instance
will be the same.