IDOC 

SAP Intermediate Documents (IDOCS) are EDI like documents that are asynchronous in nature. IDOCS are often used in sending business documents (for example sales orders) from your SAP system to a trading partner or other system. The actual TRFC call to submit the IDOC to SAP is performed synchronously and very quickly, but the actual business processing can happen at some later time defined in the SAP system. The outbound result (for example, sales order confirmation) can also happen at some later time. With RFC calls, the business processing is done immediately albeit on a different thread if we make use of the asynchronous methods described above. IDOCS offer additional queuing and retry capabilities.

SAP .NET Connector supports both submitting and receiving SAP IDOCs. The SAPIDOCSender class submits IDOCs and the SAPIDOCReceiver class can be used with a TRFC server to receive IDOCS.

To work with IDOCS you must use transactional RFC. In the SAPIDOCSender and SAPIDOCReceiver classes, SAP provides for you a TRFC client implementation that works with the appropriate function modules in SAP.