Components of SAP NetWeaver Application Server ABAP

SAP NetWeaver Application Server can be installed in various specifications depending on the SAP product and applications used. A distinction is made between ABAP systems, Java systems, and dual-stack systems. Depending on the SAP product used, not every specification may be available. The components of an AS ABAP are listed below. Optional components, such as SAP Web Dispatcher, are listed too.

Overview of the Components of SAP NW AS ABAP

Component	Description
Internet Communication Manager (ICM)	Application server component that receives and dispatches Web requests (HTTP(S), SMTP,…). ICM evaluates the URL and forwards requests to AS ABAP or AS Java accordingly.
SAP Web Dispatcher	Standalone program installed in the DMZ (demilitarized zone) that acts as a point of entry for Web requests. Web Dispatcher balances the load across the application servers and can also perform other monitoring tasks.
SAP Gateway	SAP Gateway carries out RFC services based on TCP/IP within the SAP environment. These services enable SAP Systems and external programs to communicate with one another. RFC services can be used either in the ABAP program or for the external programs using the interfaces. RFC can be used between processes of an instance or a system, or between systems.
SAP Message Server	Only one message server can run in each SAP system. It performs the following tasks in the SAP system: Central communication channel between the individual application servers (instances) of the system Load distribution of logons using SAP GUI and RFC with logon groups Information point for the Web Dispatcher and the application servers (each application server of the system firsts logs on to the message server)
SAProuter	Tool that protects the network against attacks
Standalone enqueue server	Part of the central instance (ABAP or Java) that manages the SAP locks. In combination with the enqueue replication server, this single point-of-failure can be made into a high availability solution.
SAP Start Service	The SAP start service provides the following functions for monitoring SAP systems, instances, and processes. Starting and stopping Monitoring the runtime state Reading logs, traces, and configuration files Technical information, such as network ports, active sessions, thread lists, etc.
Task handler	The task handler controls the work process and manages its resources if the work process was instructed by the Dispatcher to process a specific ABAP program.
ABAP Work Process: Update.	The update system is used to lighten the workload of the SAP transactions when time-consuming changes are made to the database. These are then carried out asynchronously in special updating work processes. The update system also avoids rollback problems that occur as a result of the differences between the logical units of work (LUW) in an SAP transaction and in the database.
ABAP Work Process: Lock Concept	The SAP system is equipped with a special lock mechanism that synchronizes database access. It prevents two parallel transactions from being able to change the same data in the database.
ABAP Work Process: Print	The following are among the main tasks of the SAP spool system: Processing and managing print requests Administering output devices Technical mapping of the output devices in the SAP system
ABAP Work Process: Background Processing	This component enables background jobs to be processed with the Computing Center Management System (CCMS). CCMS provides extensive support with scheduling and managing background jobs.