Special Edition Using SAP R/3, Third Edition

Special Edition Using SAP R/3, Third Edition - CH 3 - Exploring R/3 Architecture Page 8 of 26
The most versatile configuration employs three levels of client/server distributed processing.
In the core of the system is a high-speed network of R/3 database servers. The R/3 applications are
networked around the database cluster and have independent access to it. The R/3 applications are
fully integrated with each other.
User access to any of the applications--and hence to any of the database servers--is mediated by an
outer network of presentation servers that form the R/3 front-end systems, where they can be
integrated with PC tools and subsystems. Figure 3.1 shows a triple-level client/server configuration.
There is not a strict interpretation of level in this context, which could be referred to as multilevel
client/server configuration.
FIGURE 3.1 Triple client/server configuration.
Even Loads
Any user can be in touch with several application servers at the same time. In some areas, you might
need to balance the load by installing specialized application servers. The following areas, in
particular, are often served by systems optimized for their differing requirements:
SD-Sales and Distribution
FI-Financial Accounting
HR-Human Resources Management
Front-end and back-end computer systems are subject to different cost structures. The client/server
architecture allows an economical deployment of computing resources by separating the three server
levels.
The advantage is experienced by the user in the form of generous computing resources for the display
and prompting services that make the work easier and more effective. This can be seen in contrast to
older systems, which had to compromise between the costs of presentation support systems and the
cost of providing adequate central system resources.
From the corporate point of view, the economy of providing specialized database servers allows a
generous allocation of storage and processing resources to maintain extensive reference data and full
historical information down to the business transaction detail level.
Heterogeneous Platforms
The SAP system has been designed to cope with change, including change in the hardware and
operating systems. Therefore, the new SAP implementation must expect to integrate with the legacy
of database and presentation platforms and operating systems that have been serving the company
prior to the business process reengineering.
For example, an R/3 installation can consist of the following assembly of heterogeneous platforms, in
any combination:
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