SAP R/3 Architecture
SAP R/3 is a client/server based application, utilizing 3 tier model.
R stands for “real time data processing”.
3 stands for “three-tier system”
In this three-tier system the user interface runs on the client. To run ERP systems relatively powerful PCs (clients) and powerful servers are required where most of the hundreds of thousands of operations are performed. In a 3 tier architecture we have three layers of logic:
Presentation Layer: Graphical user interface (GUI) or browser for data entry or accessing system functions or sap easy access.
Application Layer: Back of SAP ie ABAP. Business rules, functions, logic, and programs acting on data received/transferred from/to the database servers.
Database Layer: Where databases are stored.
Two types of server communication
Access Communication
An access network includes all network segments through which the R/3 System is accessed.
It is the communication between the application servers and the presentation servers.
Access communication covers all kind of access to the R/3 System. It also includes user access through the SAP GUI, and links to other R/3 Systems and other all external applications including non sap external application..
Server Communication
A server network is the network connection between the application servers and database servers of an R/3 System.
Server communication is the communication between the application servers and the database server.