SAP Transportation Planning Interface (SD-TRA-IN) 
The SAP system offers automated support for external optimizing transportation planning, since the huge number of different possible transportation processing procedures and optimization criteria require software that is exactly adapted to the customer’s needs.
Transportation Planning Interface
Logical Communication Processes Between the SAP System and the Transportation Planning System
Application Transactions of the Interface
Configuration Options for Delivery Transfer
Description of the IDoc Segments, Fields and Domain Values