A component represented by an entry in this table may be a sub-component of another entity or unit. In this case, the value of this object indicates this entry's parent entry in this table. For example, a plug-in uplink card may be plugged into unit #3 of a stack of repeaters. In this case, this value would contain the index into this table which has a cpqnVersionUnitId of 3. If this entry has no parent, then this object contains the value zero.