SAP NetWeaver Application Server ABAP provides both the runtime environment and the development environment for all ABAP programs.
The design of SAP NetWeaver Application Server is aimed at providing an exceptionally high level of robustness and supportability for the applications running on it. Its architecture and basic terminology are explained below. For details, you should refer to the component-specific documentation.
An SAP NetWeaver Application Server ABAP system has various instances. An instance is an administrative unit containing various components of an SAP system. The components of an instance are parameterized in a shared instance profile. Each instance is identified by a system ID and an instance number.
A distinction is made between application server instances and ABAP SAP Central Services instances (ASCS instances).
There can be any number of application server instances in an SAP NetWeaver application. The instances process incoming user requests. An ABAP application server instance contains one Internet Communication Manager, one ABAP dispatcher, one gateway, one SAP start service, and any number of work processes.
As well as multiple application server instances, there is one special instance that contains the message server, the enqueue server, and a separate start service - the ASCS instance (ABAP System Central Services instance). The ASCS instance cannot process any dialog requests - it is used to manage locks, exchange messages, and balance workload in the SAP system.
SAP NetWeaver Application Server ABAP is made up of the following components:
Internet Communication Manager
ABAP dispatcher
Task handler
Any number of work processes (dialog, update, print, background, etc.)
SAP Gateway
Standalone enqueue server
SAP Message Server
The system can be enhanced with the following optional components:
SAP Web Dispatcher
SAProuter
The following figure shows the components of an ABAP system. For a better overview, series lines have not been used. Incoming requests are handled directly by the Internet Communication Manager or SAP Web Dispatcher, ABAP Dispatcher, or SAP Gateway, depending on the request type. There is one database for each ABAP system.
Administration of SAP NetWeaver Application Server ABAP