Starting an RFC Server Program Via SAProuter
An RFC server program can be started by a SAP gateway, by the currently running R/3 application server or by the currently running SAPGUI. Using the registering feature of an R/3 System Release 3.0C onwards, the RFC server program can be started before and then it registers at an SAP gateway and then waits for RFC requests.
From R/3 (RFC library and SAPGUI) Release 3.0D onwards, it is possible to start an RFC server program by a SAPGUI on a workstation (which is connected to an R/3 System) via one or more SAProuters.
According to the way of starting an RFC server program and to the Release of the SAP System, there are different ways for RFC server programs to work with SAProuters.
Using the Registering Feature
Program Start by Application Server
Program Start by SAP Gateway
Program Start by SAPGUI