Architecture of the SAP NetWeaver Application Server 

Purpose

The SAP NetWeaver Application Server is the central foundation for the entire SAP software stack. It also provides a platform for other NetWeaver components (Portal, XI, and so on), as well as for ABAP and Java applications. The full J2EE standard is supported. The SAP NetWeaver Application Server is the further development of the SAP Web Application Server.

Design

The design of the SAP NetWeaver Application Server is aimed at providing an exceptionally high level of robustness and maintainability for the applications running on it.

With VM Container technology SAP has achieved a technological foundation that allows Java applications to be executed with a similar level of robustness as software developed in ABAP. The aim is to isolate individual users from each other as securely as possible to avoid any unwanted restrictions.In order to provide an optimal runtime environment for selected scenarios with especially high demands on a narrow ABAP-Java coupling, in this release a Java VM can also run integrated in the ABAP work process.

For more information about this see Architecture of the VM Container.

Technical Components

An SAP system consists of several application server instances, as well as one or more databases.

In addition to the whatever number of dialog instances users choose to execute, there is one central instance that contains the message server and the enqueue server. It cannot process any dialog requests.

A dialog instance consists of the following components:

·        The Internet Communication Manager (ICM) sets up the connection to the Internet. It can process both server and client Web requests.It supports the protocols HTTP, HTTPS, and SMTP. The SAP Web AS may be a Web server or a client (see SAP Web Application Server: Web Server or Web Client)

·        The dispatcher distributes the requests to the work processes. If all the processes are occupied the requests are stored in the dispatcher queue.

·        The Work Processes execute ABAP or Java programs.

·        The SAP Gateway makes the RFC interface between the SAP instances available (within an SAP System and beyond system boundaries).

·        The Message Server exchanges messages and balances the load in the SAP system.

·        In the J2EE component of the SAP NetWeaver AS there are also components Java Dispatcher, Server Process and Software Deployment Manager For more information see Java Cluster Architecture.

The graphic below shows these components. To retain clarity a few communication channels are not included in the graphic.

Integration

There are the following installation options for the SAP NetWeaver AS:

·        ABAP System (with integrated VM Container). In the graphic these are the components in the blue box on the left. With this installation you can run ABAP programs and selected SAP Java applications.

·        Java system. In the graphic these are the components in the green box on the right. With this installation you can run J2EE applications but not any ABAP programs.

• ABAP+Java system. These are all the components in the graphic. For more information see SAP NetWeaver Application Server with ABAP and Java.

Further Information

For information on related topics, see the following documentation:

Architecture of the VM Containers

Architecture of a Web AS Java System (J2EE Cluster)