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India SAP CoE, Slide 1

AB1001 - R/3 Overview &

Architecture v1.0

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Topics Covered

1 Defining R/3

2 Why R/3 ?

3 SAP R/3 Architecture

4 Summary

5 Annexure

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Topics

1

2

3

4

5

Defining R/3

Why R/3 ?

SAP R/3 Architecture

Summary

Annexure

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R/3

R/3 software supports all of a companys business transactions and links

them together using real-time integration.

Real-time integration means that each change or update in one

application causes the automatic change or update of the data in the

other applications involved.

R/3 means Real-time 3-tier Architecture

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R/3

Sales and

Distribution

Finance and

Controlling

Human

Resources

Production

Planning

Materials

Management

What Does R/3 Do in SAP?

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R/3

R/3 also represents 3-tiered Client-Server Architecture.

The three Logical Layers of this R/3 Architecture are

The Presentation Layer : Collects user input and creates

process request.

The Application Layer: Uses the Application logic of Program tocollect and process the process request.

The Database Layer: Stores and Retrieves all Data.

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R/3

1. Presentation / GUI Layer : The presentation or GUI layer typicallyreceives keyboard/mouse data from a user and sends that data in the formof process requests to the application layer for further processing. Whenlayer receives output from the application layer it reformats the data andpresents textual and graphical data to the users PC screen.

2. Application Layer : The application layer consists of R/3's corecomponents. The majority of R/3 business logic processing occurs in theapplication server layer. This is where the work processes are managed bythe dispatcher.

3. Database Layer : The database layer contains an engine whose solemission is to store and retrieve data on behalf of the application layer.SAP R/3 uses the industry standard database access language SQL(pronounced SEE-QUEL - Structured Query Language) as an interfaceto access its supporting database

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R/3

reside in: reside in:reside in:

Physical Distribution of R/3sLogical Layers

Database Layercomponents

Application Layercomponents

Application servers:

Specialized systems

multiple CPUs and

vast amounts of RAM.

Application servers:

Specialized systems

multiple CPUs and

vast amounts of RAM.

Presentation servers:

Systems capable of

providing a

graphical interface.

Presentation servers:

Systems capable of

providing a

graphical interface.

Presentation Layercomponents

Database servers:

Specialized systems

with fast and large

hard drives.

Database servers:

Specialized systems

with fast and large

hard drives.

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By now you are aware of

What is R/3 ?

What does R/3 mean ?

R/3

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Topics

1

2

3

4

5

Defining R/3

Why R/3 ?


Summary

Annexure

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Why R/3 ? The main purpose of an R/3 system is to provide a suite of tightly

integrated, large-scale business applications. The standard set ofapplications delivered with each R/3 system are the following:

PP (Production Planning)

MM (Materials Management)

SD (Sales and Distribution)

FI (Financial Accounting)

CO (Controlling) AM (Fixed Assets Management)

PS (Project System)

WF (Workflow)

IS (Industry Solutions)

HR (Human Resources)

PM (Plant Maintenance) QM (Quality Management)

These applications are called the functional areas, orapplication areas,or at times the functional modules of R/3. All of these terms aresynonymous with each other.

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Why R/3 ?

In above scenario where information flow is required on immediate base only

R/3 is viable option

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Why R/3 ?

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Why R/3 ?

By now you know

What is R/3 ?

What does R/3 mean ? Why & in what situation is R/3

required ?

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Topics

1

2

3

4

5

Defining R/3

Why R/3 ?


Summary

Annexure

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We know that, SAP R/3 is software, in particular it is client-serversoftware. This means that the groups/layers that make up a R/3System are designed to run simultaneouslyacross several separatecomputer systems.

When a company installs SAPs software, each component (or

layer in R/3s case) is stored, managed, and processed via thehardware of separate and specialized computer systems.

Each layers is capable of calling upon the specialty of any of theother installed layers in order to complete a given task.

Those components/layers that are requesting services are called

clients, those components/layers that are providing services arecalled servers. Thus the term - client/server.

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The Database Layer

components are installed on

one high -end database server.

The Application Layer

components are installed

across one or more

high -end servers.

Physical Distribution of SAP R/3s Three

Layered Client/Server Architecture

Presentation Layer components are installed across many PCs.

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It is important to note that each and every installed copy of SAP R/3always interoperates as a logical three layered client/server system.

In certain sub-optimal cases multiple logical layers may coexist on thesame physical computer.

Nevertheless, SAP R/3 always works as a three layered client/serversystem.

From next slide youll see examples of how R/3s layers can bedistributed across one or many computers.

The arrangement of the logical layers across computers is referred toas a systemsclient/server configuration

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SAP R/3 Architecture Centralistic: All SAP R/3 layers reside on the same physical computer.

One important distinguishing characteristic between the various R/3 client/serverconfigurations is Scalability. If a configuration is scaleable, adding additionalcomputers to the system will increase the overall performance of the system.

Centralistic client/server configurations are not scaleable at all. Consequently, thisconfiguration is never used in a production environment. SAP has actually installed anentire SAP R/3 system on a notebook computer for use by SAPs salesrepresentatives.

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SAP R/3 Architecture Distributed presentation: The presentation layer is rolledout to desktop PCs. The

application layer and the database layer are installed on the same computer.

In terms of increased performance, the Distributed presentation configuration is nomore scaleable than the centralistic configuration. This configuration is verymainframe-ish.

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SAP R/3 Architecture Two-tier client/server: The presentation and application layers are installed on the

same computer. The database layer is installed on a separate computer. Two-tier client/server configurations offer increased scalability.

However, two-tier client/server configurations create other problems. Thecommunication across the network between the front-end (presentation andapplication layers) and the backend (database layer) becomes a bottle-neck veryquickly.

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SAP R/3 Architecture Three-tier client/server: Presentation, application, and database layers run on separate

computers. Currently, three-tier client/server offers the best solution for most businesses. It is

highly scaleable, and offers better distribution of process requests received from theusers. The computers in the application layer are often capable of satisfying the usersprocess requests without accessing the database, which in turn boosts performance.

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SAP R/3 Architecture Multi-tier, cooperative client/server: All layers run on separate computers. But what

makes it different is that this configuration is scaleable on the backend (databaselayer) as well.

This is becoming a very important technology as more and more organizationsattempt to implement SAP R/3 globally. In such a case one central database is notfeasible. New technologies such as SAPs Application Link Enabling (ALE), andOracles Parallel Server are making multi-tier, cooperative client/server a growingreality

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SAP R/3 Architecture- Processes PROCESSES are used to efficiently manage the software applications requests for the

resources of the operating system. The process and the software application are veryclosely linked.

Each process has memory and access to system resources. A process comprises:

o An executable program that defines initial code and data

o A memory address space where theprocesss code and data are stored

o System resources

o At least one thread to execute the code.

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SAP R/3 Architecture - Thread A THREAD is a single unit of execution. It is the actual component of a process that is

executing at one time.

It runs in the address space of the process, using resources allocated to the process.Each thread is capable of completing a different task that its process requests.

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SAP R/3 Architecture - Kernel Multi-threading operating systems, like Windows NT and UNIX are capable of

executing more than one thread at a time. At the heart of an operating system is theKERNEL.

It is the responsibility of the operating systems kernel to manage the time of the CPU.It must keep each of the processes that are attempting to accesses the CPU in harmony.It is capable of changing the priority the threads from each of the processes that areattempting to get processing time on the CPU.

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In the center of the R/3 Basis Kernel is SAPs proprietary control agent, the SAP

DISPATCHER. Together with the respective operating system, the dispatchermanages the resources used by the R/3 applications.

It must Communicate with the operating systems kernel to manage the activities ofits processes.

SAP R/3 Architecture - Dispatcher

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Throughout the R/3 System, you can be assured that where there are work processes

there will be a dispatcher. The exact number of work processes is variable and dependson the specific configuration. The main purposes of the dispatcher is to dole outpending processing requests to the work processes.

There are special work processes for:

Interactive SAPGUI screen processing (the dialog (online) work process)

Updating of the database (the update work process)

Background processing (the background (batch) work process) Spooling (the spool work process)

Management of locks (the enqueue work process)

The dispatcher acts like a conductor, orchestrating the assignment of the correctresources to the processing requests that are received from the end-users.

The specific tasks of the dispatcher are:

To maximize efficient distribution of process requests to work processes

To monitor the use of the R/3 buffers

To ensure process requests are sent back to presentation level when completed.

Managing of communications activities.


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First, user input is accepted by SAPGUI.

SAPGUI converts the users input into process requests that the dispatcher canunderstand, and then sends the process requests to the dispatcher.

After receiving the process request, the dispatcher places it into the requestqueues.

As work processes become available, the dispatcher dispatches the queuedprocess request to the appropriate work process.

Work processes are specialized components of the SAP software that aredesigned to do very specific activities.

For example if the dispatcher receives a process request to print a report, thatprocess request will inevitability find its way to the work process that managesthe print spool.

When processing is complete, the result of a work process is returned, via thedispatcher, to the SAPGUI. The SAPGUI interprets the received data andgenerates the output screen for the user.


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A service is a process or group ofprocesses that perform a specific systemfunction (i.e., service) and often provide an application programminginterface (API) for otherprocesses to call.

Many services start at boot time and continue to run as long as thesystem is up

SAP R/3 Architecture - Service

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A set of R/3 work processes that are started and stopped in unison as wellas the associated supporting underpinnings such as an operatingsystem, TCP/IP networking software and a supporting server hardware.

SAP R/3 Architecture - Instance

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The single regular instance for each unique R/3 system whose profileincludes the single enqueue and single message service for that uniqueR/3 system.

The messaging service manages internal communication.

A single Central Instance is grouped together with multiple regularInstances to form a System

SAP R/3 Architecture Central Instance

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The message service is used by the application servers to exchangeshort, internal messages (for example, trigger an update,enqueue/dequeue, trigger a background job)

Every application server reports to the message service with a uniquename

SAP R/3 Architecture Message Service

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While short messages can be exchanged between an R/3 Systemsapplication servers via the message server, larger quantities of data(application data) are transferred via the SAP gateway.

The communications partner can be in the same system, a different R/3 orR/2 System, an external program

SAP R/3 Architecture Gateway Service

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Remote Function Call (RFC)

The RFC interface enables function calls between two SAP systems (R/3or R/2), or between an SAP system and an external one. The RFC libraryfunctions support the C programming language and Visual Basic (onWindows platforms).

SAP R/3 Architecture RFC

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SAP system is a single, logical, separate and independent copy of R/3. Inother words, everything that uses the same database.

SAP R/3 Architecture SAP System

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By now you know

What is R/3 ?

What does R/3 mean ? Why & in what situation is R/3

required ?

Detailed Architecture of SAP R/3


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Topics

1

2

3

4

5

Defining R/3

Why R/3 ?


Summary

Annexure

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Summary

SAP R/3 is SAP's integrated software solution for client/server anddistributed open systems.

SAP's R/3 is the world's most-used standard business software forclient/server computing.

R/3 meets the needs of a customer from the small grocer with 3users to the multi-billion dollar companies.

The software is highly customizable using SAP's proprietaryprogramming language, ABAP/4.

R/3 is scalable and highly suited for many types and sizes oforganizations.

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Topics

1

2

3

4

5

Defining R/3

Why R/3 ?


Overview

Annexure

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Annexure

SAP R/3 : Systems Applications &

Product in Real-time 3-tier

Architecture.

Pronunciation: SAP (Ess Aay

Pee).

Documents

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