Maintaining the Distribution Model 
Use
The distribution model describes the ALE message flow between logical systems. The relationships between logical systems, message types, BAPIs (Business Application Program Interfaces) and filters are defined in the distribution model. Both applications and the ALE layer use the distribution model to determine receivers and to control the data distribution.
Prerequisites
The logical source system (R/3 System) and the logical target system (external CSD system) from and to which the
IDocs are sent, must be specified in the Implementation Guide (IMG) for each outbound IDoc.Procedure
Result
In the following example, TDDCLNT010 is the logical for the R/3 current system and WM_PARTNER is the logical system for the CSD external system.

