SAP system landscape is defined as an arrangement of SAP servers. In a Sap environment, a three-system landscape exists. A system landscape consists of 

1) Development Server 

2) Quality Assurance server 

3) Production Server 

SAP Architecture is different from the SAP landscape. SAP architecture is a technology that can be changed from time to time unlike the SAP landscape can’t be changed.

   What is SAP R/3 Architecture?

The image given below shows the 3-tier architecture of the SAP system.

1.    Presentation

2.    Application

3.    Database

In simple words, it’s a client-server architecture.

·         R signifies Real-time system

·         3 represents - 3-tier architecture.



Presentation Layer:

The Presentation Layer contains the software components that make up the SAPgui (graphical user interface). This layer is the interface between the R/3 System and its users. 


The presentation layer sends the user's input to the application server and receives data for display from it. While a SAPgui component is running, it remains linked to a user's terminal session in the R/3 System.

Application Layer:

The Application Layer consists of one or more application servers and a message server. Each application server contains a set of services used to run the R/3 System. Theoretically, you only need one application server to run an R/3 System. The message server is responsible for communication between the application servers. It passes requests from one application server to another within the system. It also contains information about application server groups and the current load balancing within them. It uses this information to assign an appropriate server when a user logs onto the system.

Database Layer:

The Database Layer consists of a central database system containing all of the data in the R/3 System. The database system has two components - the database management system (DBMS), and the database itself. SAP has manufactured its own database named HANA but is compatible with all major databases such as Oracle. All R/3 data is stored in the database. For example, the database contains the control and customizing data that determine how your R/3 System runs. It also contains the program code for your applications.


DEVELOPMENT ------>>> Quality ------->>> PRODUCTION



Understanding the components of SAP R/3 3-tier Architecture:-

1.    Message Server: 

     It handles communication between distributed Dispatchers in the ABAP system. Its main purpose is to load balance the system (when more than one Dialog instance is configured) It is also used to handle the lock requests that are initiated from dialog instances. There will be only one message server in the entire system.

2.    Dispatcher Queue: 

      Various work process types are stored in this queue. Queue in which the requests for the various work process types are collected. The dispatcher queue contains a queue for dialog requests, a queue for spool requests, and a queue for lock requests, depending on which work process types are configured in this instance.


3.  Dispatcher: 

     It distributes requests to the work processes. SAP Dispatcher is part of SAP Net weaver Application server. Its job is to handle the user requests and distribute them to work processes.

Dispatcher distributes the requests to the work processes. If all the processes are occupied then the requests are stored in dispatcher queue.

4.  Gateway: 

     It enables the communication between SAP system and between SAP system and external systems.

5.  ABAP-Work processes: 

     It separately executes dialog steps in R/3 applications.

          Types of work processes are given as below:-


    1. Dialog work process:              Responsible for dialog process.

    2. Update work process:             Responsible for Update

    3. Update 2 work process:          Responsible for the less critical update.

    4. Background work process:    Responsible for background job.

    5. Spool work process:               Responsible for output requests.

    6. Enqueue work process:           Responsible for the lock.


6.    Memory-pipes: 

     It enables the communication between ICM and ABAP work processes.

7.    Enqueue Server:

     It handles logical locks that are set by the executed Java application program in a server process.