Program Start by Application Server
Program start by application server means that the RFC server program will be run on the same machine as the application server. In this case, you have different application servers of an R/3 System running on different networks connected via SAProuter.
From R/3 (RFC library and SAPGUI) Release 3.0D onwards, it is
posssible to start an RFC server program by a SAPGUI on a
workstation which is connected to an R/3 application server.
This application server has two networks: