SAP R/3 Architecture

The SAP R/3 System architecture consists of three layers: Presentation, Application, and Data Storage.The following diagram illustrates the functions  (Request & Response) done by each layer and how the layers work together:

Presentation

This is where users of the SAP R/3 System will submit input to the SAP R/3 System for the processing of their business transactions.It is also where the output from these transactions appears as output fields, reports, tables and spread sheets.

Application

This layer consists of  Presentation Components, SAP Applications, Kernel & Basis Services and ABAP Workbench.

1. Presentation Components : The presentation components are responsible for the interaction between the R/3 System and the user. Based on the request received, presentation components inform to the client system, which screen should be presented to the end user.
2. SAP Applications : An appropriate SAP Application responsible for accomplishing the request is identified by the presentation components & is provided to the kernel & Basis services.
3. Kernel & Basis Services : It provides the run time environment to process the SAP Application along with the data & return results to the end user.
4. ABAP Workbench : It is a development environment that provides the necessary tools to develop new SAP Applications or customize the existing SAP Applications.

Database

Each SAP R/3 System is linked to a database system, it consisting of a database management

system (DBMS) and the database itself. The applications do not communicate directly with

the database. Instead, they use Basis services.