tRFC
Via tRFC, data can be transferred safely and reliably between applications. The RFC client calls a specific function module on the RFC server. The called function module is executed exactly once on the server. The resulting data is then stored temporarily in the SAP database under a unique transaction ID (TID), that is, data creation and data transmission are two separate processes. The tRFC is used for example to send business documents from one SAP system to another SAP system, often by using the ALE/IDoc layer.
One or several functional module calls can be grouped into a single tRFC LUW (logical unit of work). Due to its asynchronous nature, the tRFC can handle situations where the called remote system is not available at the time of posting. In such a case a reprocessing is triggered by the tRFC framework.