Classes are used in master data management when distribution rules cannot be mapped across organizational units. There are classes for material, customer and vendor master data.
As cost centers and G/L accounts are not classified, they cannot be distributed in classes. Since the quantities of data in these cases are small, all the data can be distributed to all the systems. You can also filter the data by organizational unit.
Classes can be used to define the master data objects which a given system needs to know about.
The Hamburg system needs to know all the purchasing data in the WHOLE class (range of wholesale goods) and also all the sales data in the SOUTH class (materials sold in the south of the country).
For each object type a (customer-defined) class type can be specified as relevant for ALE. All classes belonging to this class type can be used.
Classes are maintained in master data transactions. To add a master data object to a class, you simply classify it.