March 30, 2018 R/3 Architecture: In SAP R/3, SAP stands for System, Application and Product. Where R is for Real-time and 3 represents the three-tier client-server architecture. Hence SAP R/3 System has a three-tier client/server architecture named it as R/3 Architecture. It consists of three Layers Presentation Server/ Layer/ Tie Application Server Database Layer Presentation Server: It is the end layer and allows users to interact directly with SAP system. This is the only layer from where users connect to the SAP system. DIAG (Dynamic Information Action Gateway) is the protocol which is used to communicate between user and SAP system. Using this we can have our own font settings and our own languages settings. It is an intelligent and user-friendly server. It is an operating system and database independent. It is a client for all the SAP Solutions. SAP R/3 is also referred as SAP GUI. There are three 3 types of SAP GUI SAP GUI for windows (On Windows OS) SAP GUI for JAVA (On all OS where JAVA is supported) SAPGUI for HTML (for web-based) Application Server: It is used to handle the user request and process them to the database. It has a dispatcher to process and monitor the user request, work process to interpret the requests, Buffer areas to store all the frequently accessed data. It absorbs the load both from the client and the server. Database server: It is the layer where the database is hosted. It has its own memory areas, buffer areas, work processes etc. A central RDBMS realizes the database layer of SAP R/3 systems. Initially, SAP database will use open SQL but database client will convert open SQL into native SQL. That is the reason SAP supports different databases. It is the area where the complete data resides. It has its own queue, process, buffers and request handling mechanism.