This is an integer type identifier for this unit. The values of this integer are administered by allocating a MIB object identifier for each type of unit from a common branch. The value of this object is then the last level in that identifier. The values are defined in this MIB module. Note that the values are unlikely to be contiguous. Note that if a type value is not available for this unit then this object will return zero. There are several reasons why this value may not be available through this view of the MIB. One reason may be that the device is not currently active (dead) or that the information is only available through the units own agent (see stackUnitManagementType) .