The Role, Function and
Use of ITS (Internet
Transaction Server) in
mySAP.com Solutions
Technical Brief
Enterprise Systems Group (ESG)
Storage Systems Group (SSG)
Dell White Paper
By Dell SAP CC Walldorf
August 2001
Contents
Executive Summary ...............................................................................3
Introduction ............................................................................................4
Target Audience ..............................................................................4
Introduction .....................................................................................4
Description of Internet Transaction Server (ITS)............................5
Overview ..........................................................................................5
Description of a request cycle with HTTP/SAPgui protocol
transition ...........................................................................................6
Planning the System ...........................................................................10
Sizing Fundamentals And Recommendations ........................11
Calculation of Active Users for One Service ........................................ 12
Hardware Recommendations .....................................................12
Conclusions/Recommendations .......................................................14
Contacts ...........................................................................................14
Appendix A: Reference Documents ................................................16
Appendix B: Glossary of Terms and Acronyms ...........................17
Appendix C ...........................................................................................18
Vendor Information ............................................................................18
SAP ..................................................................................................18
Dell Computer Corporation ........................................................18
Intel Corporation...........................................................................19
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Section
1
Executive Summary
When implementing a mySAP.com solution from SAP, the link between the
Internet and the SAP system itself is accomplished with SAP’s Internet
Transaction Server (ITS). The purpose of this paper is to explain the role, function
and use of ITS within the SAP solution and how to leverage Dell’s architecture to
construct a resilient ITS environment.
As a pioneer in using Internet technology to create e-commerce success, Dell is
well positioned, as a mySAP.com Global Technology Partner, to probe the use of
ITS and how it can be best implemented for Dell’s customers’ benefit in an
optimized SAP landscape.
Further, proven solutions are the key to any IT strategy. The results contained in
this paper are the result of extensive testing done at Dell’s SAP Competence
Center and Dell personnel working in SAP’s LinuxLab at SAP headquarters in
Walldorf, Germany as well as drawing on the expertise of Dell’s Solution
Engineering team at Dell’s worldwide headquarters in Round Rock, Texas, USA.
Customer feedback and experience from the field in over 1,500 SAP installations
running on Dell™ PowerEdge™ servers and PowerVault™ storage worldwide
have also been incorporated into this report.
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Section
2
Introduction
Target Audience
This paper is targeted toward Dell technical sales representatives, systems
consultants and field technical personnel, and customers who have a need to
deploy an SAP Internet Transaction Server as part of their SAP solution on Dell
PowerEdge server and PowerVault storage systems.
Introduction
SAP customers wanting to harness the power of the Internet, may use SAP
Internet Transaction Server (ITS) as the gateway between SAP and the Web. This
allows for interactive Web access to the SAP system.
The purpose of this paper is to outline the roles, functions and use of ITS in an
SAP environment. This is of particular importance as more SAP customers
upgrade their systems’ active users to SAP’s Web-enabled functionality. Dell has
already seen a huge increase in demand for PowerApp appliances and
PowerEdge servers necessary to build the Internet infrastructure for SAP
systems.
Particular attention will be paid to the manner in which a resilient, redundant
ITS configuration is created, as the scalability of the ITS product allows for many
possible scenarios.
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Section
3
Description of Internet Transaction Server
(ITS)
Overview
HyperText Transfer Protocol (HTTP) is the main protocol used on the World
Wide Web for the communication between Web Browsers and Web Servers for
the transfer of documents such as HTML (HyperText Markup Language)
documents. HTML is an authoring language used to describe a document’s
representation on the Internet. HyperText Markup Language documents refer, or
connect, to other documents by hyperlinks. These inter-linked documents form
the structure of the World Wide Web.
As stated earlier, ITS acts as a gateway between the SAP application server layer
and HTML Web technology, thereby allowing interactive Web access to an SAP
system. The conventional method of accessing the SAP system interactively is by
using an SAP GUI (Graphical User Interface), which is available in different
“flavors” such as “SAP GUI for Windows”, “SAP GUI for Java” and “SAP GUI
for HMTL”. An SAP GUI displays SAP transaction screens and allows the user to
interact directly with the system. It communicates with the SAP System by using
a special SAP GUI protocol. Without ITS, a user would need additional
middleware to access the SAP System with a Web browser in order to make the
connection between SAP technology, such as SAP application servers and SAP
GUIs, and Web technology, including Web servers and browsers. This necessary
connection is accomplished by ITS and the need for additional middleware is
eliminated. ITS dynamically maps the SAP transaction screen elements to HTML
and does not do any transaction processing itself. Instead, it hands all business
processing over to the SAP system on an application level. The ITS is merely a
presentation front end.
ITS consists of two main program components: WGate (Web Gateway) and
AGate (Application Gateway), which may exist on the same host or on separate
hosts, with or without an intermediate firewall, connected by a TCP/IP network.
Figure 1 provides an overview of the ITS architecture including WGate, AGate
and the communication protocols used between them. Figure 1 also details a user
request cycle using an HTTP/SAP GUI protocol transition.
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3
H T T P S e rv e r
2
Internet Transaction Server
Browser
HTTP
9
ISAPI
NSAPI
W G ATE
Web Server
1
4
F
I
R
E
W
A
L
L
AGATE Session
Layer
Session
State
Context
MetaHTML
Interpreter
I/O Abstraction
Layer
Resource
Files
(HTML
Templates,
Service,
Language)
Figure 1: SAP Internet Transaction Server Architecture
Description of a request cycle with HTTP/SAPgui protocol transition
The following steps depict a request cycle with an HTTP/SAPgui protocol
transition as seen above.
1.
A user request is received via Web browser (Internet Explorer, Netscape ®
Navigator™, etc.).
2.
The Web server (e.g. Microsoft® Internet Information Server (IIS), Netscape
Enterprise™, Apache) redirects to WGate.
3.
WGate sends a prepared request to AGate on the other side of the firewall.
4.
A service file is loaded automatically and processed by AGate (interpretation
and composition).
5.
Transmitted data is received by the Internet application component and
executed in the SAP application server (using BAPI methods).
6.
Results are transmitted back to the AGate component in ITS.
7.
By loading HTML templates and pages and inserting the application results
into defined fields, the HTML output page is composed by AGate output
processing.
8.
The HTML page is sent back to the WGate and the Web server.
9.
Data is displayed on the Web browser screen as a true HTML document.
When looking at the ITS server(s) in a real SAP environment, it becomes clear
that these servers are the “glue” that holds together the Internet Application
mySAP.com. The AGate especially, is not just a data repository. Rather, its builtin functions and responsibilities, which include screen mapping by translation
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5
SAP
7
8
SAPgui
Protocol
Dell ESG Worldwide Marketing
6
and interpretation, and session and connection management with an underlying
SAP application server, make it the most essential part of the Internet
Transaction Server. Figures 2, 3 and 4 are examples of the SAP ITS look, feel and
functionality.
Figure 2: Example of ITS Administration Overview Screen
In general, the ITS is a multi-threading gateway service. Threads are assigned per
request/response cycle (not per user session), which results in better performance
because threads are re-usable after they have been released of the former user
request. In order to provide fast context switching and low latency, ITS has its
own memory management, which is very efficient, thus enabling the
management of many simultaneous sessions per period.
One of the main functions of the WGate component is to provide the
establishment of a “stateful” session with an SAP system via the “stateless”
communication channel (“per-request-connection”) of a typical Web
server/browser combination. Internal Web server APIs such as Netscape
Enterprise Server, Microsoft IIS, and Apache Web Server are supported in
addition to the standard CGI (Common Gateway Interface) functions. The
WGate portion of ITS resides on the same system as the WEB server.
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Figure 3: Example of ITS Administration Process View Screen
With ITS release 4.6D, WGate is capable of communicating with more than one
AGate simultaneously via IP link, regardless of where the AGate is physically
installed – on the same host or on a different one. It is not necessary to have a
dedicated virtual Web server per virtual ITS. Additionally, with release 4.6D
compilation 3, ITS is patchable, which means, in order to apply improvements to
an ITS installation, it is no longer necessary to uninstall the former ITS and then
have the revised server newly installed.
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Figure 4: ITS Control Screen
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Section
4
Planning the System
In order to provide the resilience and redundancy necessary for productive use,
at least two Internet Transaction Server instances on different hosts should be
used for the implementation of SAP ITS. This recommendation applies to the ITS
as well as to the Web server instances associated with WGate.
Figure 5: Example of ITS topology in an SAP configuration
The whole ITS environment is scalable by means of additional server systems
with ITS and Web server instances. Depending on the size of the SAP system to
be implemented, new ITS instances can be established and connected as needed.
Load balancing on the Web side can be provided by a PowerApp.BIG-IP solution
(sessions are maintained in the AGate), whereas the AGate must not reside in the
WGate/Web server system.
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Sizing Fundamentals And Recommendations
Note: The following specifications and numbers are mainly based upon SAP’s
experience with on-site installations and benchmark tests using standard SAP business
applications.
To get the best sizing results possible, it is necessary to identify the number of
concurrent users who will access the SAP system over ITS in each of the different
components of the mySAP solution used. The types of users can be distinguished
by the kind of load they generate:

Continuous load - e.g. order entry and address changes

Peak load services - e.g. time sheet services and other Employee Self
Services (ESS), which are active per user for short periods of time (once a
week for instance)
For more information on sizing in a mySAP.com environment, refer to the Dell
Technical Brief, Effectively Sizing a mySAP.com Solution. (See
http://www.dell.com/downloads/us/pedge/sap_sizing_wp.doc)
For continuous load applications, an average load per time frame can be used,
such as number of documents per day, or orders per week. This transactional
load can also be broken down into simple, more characteristic dimensions.
For peak load services, the characteristic high load period has to be identified.
For instance, the top, or high load period for Time Sheet service may be found
early Friday afternoon at one o’clock for four hours. Other services may have a
different time point for their peak load.
For all the services, the average time per user transaction has to be estimated or
measured. This will be dependant on the number of transaction steps, the
duration of each step, and a “think time” of approximately 30 seconds.
For a specific SAP module, the following formula describes the characteristics of
the system load:
Active users = (Number of transactions / time frame) * average transaction time.
This calculation has to be done iteratively for each module that will be accessed
via Internet Transaction Server. The following example demonstrates how to
calculate the number of active users for one service. In this particular example,
the service application is a peak load service being used during a high load
period.
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Calculation of Active Users for One Service
Number of active users for the service application Time Sheet (peak load service)
Formula: Active users = (number of transactions / time frame) * average transaction
time.
Calculation example:



Number of transactions = 1,000 per week (1,000 employees have to make
a time sheet entry every week)
Time frame (High load period) = 4 hours, or 240 minutes, on Fridays
from 1 p.m. to 5 p.m. (worst case)
Average transaction time = 15 minutes, based on 30 transaction steps
with 30 seconds “think time” per step
Number of active users = (1,000 named users / 240 minutes) * 15 minutes
= 63 active users (medium activity) for Time Sheet Application.
Hardware Recommendations
The following table gives a high level overview of server configurations for
specific numbers of active users for ITS. When the Internet Transaction Server is
divided into separate systems, one for WGate and a second one for AGate, the
proposed configurations apply to the server hardware with the AGate
component. The WGate resides on the Web server system, whose configuration
can be determined by an adequate Web server sizing taking into account an
added CPU performance requirements for the WGate service. Table 1 provides a
high level overview of server configurations for ITS based on the number of
active ITS users. The recommended system configurations assume a dual host
ITS landscape for redundancy and resilience, as mentioned earlier.
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Table 1: Recommended System Configurations Based on the Number of Active
ITS Users
Size
A
Number of Active
ITS Users
0 - 250
B
251 - 500
C
501 - 1000
D
1001 - 3000
E
> 3000
(Quantity) Platform
(2) PowerEdge 2450/2550
(1) Intel Pentium III, 866 MHz
256 MB RAM
(2) HDSK 18 GB, RAID-1 (OS+Swap)
(2) PowerEdge 4400
(1) Intel Pentium III XEON
512 MB RAM
(2) HDSK 18 GB, RAID-1 (OS+Swap)
(2) PowerEdge 4400
(2) Intel Pentium III XEON
1 GB RAM
(2) HDSK 18 GB, RAID-1 (OS+Swap)
(2) PowerEdge 6450
(4) Intel Pentium III XEON w/ 1 MB L2
Cache
2 GB RAM
(2) HDSK 18 GB, RAID-1 (OS+Swap)
(n)* PowerEdge 6450
(4) Intel Pentium III XEON with 2 MB
L2 Cache
2 GB RAM
(2) HDSK 18 GB, RAID-1 (OS+Swap)
* The number of PE 6450’s will depend on an exact sizing.
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Section
5
Conclusions/Recommendations
In this paper, Dell has outlined the vital role, function, and use of the SAP
Internet Transaction Server in mySAP.com solutions. Without the careful and
planned implementation of the ITS server, no SAP solution today can be
effectively Web enabled.
It is essential that care be taken in ensuring the setup of a resilient and scalable
ITS implementation. The ITS Server is continually being updated by SAP to take
advantage of new technologies and make ITS increasingly easier to install and
service. Dell PowerEdge servers and PowerVault storage are particularly well
suited to provide the ITS functionality required in any sized SAP environment.
Contacts
The information in this document describes results from Dell’s installation and
testing with ITS on Dell servers and storage. If needed, Dell has scripts, tools
and consulting services/labs available to help companies do their own proof of
concept. For questions about this paper or the implementation of SAP Internet
Transaction Server with Dell PowerApp, PowerEdge and PowerVault hardware,
please contact a Dell sales representative. For comments, questions or feedback
about this paper, please send email to us_solutions_engineering@Dell.com.
Solution Enablement Lab and Showcase
Enterprise Systems Group/Storage Systems Group
Dell Computer Corporation
One Dell Way
Round Rock, Texas USA 78682
+1-(800) WWW-DELL (999-3355)
or +1-(512) 338-4400
us_solutions_engineering@Dell.com
www.dell.com
Dell, PowerEdge, PowerApp and PowerVault are trademarks of Dell Computer Corporation. Microsoft and IIS are either
registered trademarks or trademarks of Microsoft Corporation. Netscape, Netscape Navigator and Netscape Enterprise
are either registered trademarks or trademarks of Netscape Communications Corporation in the U.S. and other countries.
Intel, Pentium, Pentium III Xeon, and Itanium are registered trademarks or trademarks of Intel Corporation.
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Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and
names or their products. Dell disclaims proprietary interest in the marks and names of others.
©Copyright 2001 Dell Computer Corporation. All rights reserved. Reproduction in any manner whatsoever without the
express written permission of Dell Computer Corporation is strictly forbidden. For more information, contact Dell. Dell
cannot be responsible for errors in typography or photography.
Information in this document is subject to change without notice.
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Section
7
Appendix A: Reference Documents
The following documents are helpful reference materials for deploying ITS:
August 2001

Dell Technical Brief, “Effectively Sizing a mySAP.com Solution.” See
http://www.dell.com/downloads/us/pedge/sap_sizing_wp.doc.

Information on the Internet Transaction Server can be found on the SAP
Service Marketplace at www.service.sap.com (a user ID is required and can
be obtained immediately). After logging on, go to “Infrastructure and
Services”, then “mySAP Technology”, and then under “More Technologies,
click on “Internet Transaction Server”. Once a user ID and password has
been established, the following URL can also be used for direct access to the
ITS Service Marketplace Web page: http://service.sap.com/sap-its.
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Appendix B: Glossary of Terms and
Acronyms
B2B – Business-to-Business
B2C – Business-to-Consumer
CRM – Customer Relationship Management
ERP – Enterprise Resource Planning
ESG – Enterprise Systems Group
ISP – Internet Service Provider
ITS – Internet Transaction Server – A portion of any mySAP solution that
requires use of the World Wide Web
AGate – Application Gate component of the Internet Transaction Server
WGate – Web Gate component of the Internet Transaction Server
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Appendix C
Vendor Information
SAP
Founded in 1972, SAP (NYSE: SAP) is a recognized leader in providing
collaborative e-business solutions for all types of industries and for every major
market. Headquartered in Walldorf, Germany, SAP is the world's largest interenterprise software company, and the world's third-largest independent
software supplier overall. SAP software is deployed at more than 30,000 business
installations in more than 120 countries and is currently used by companies of all
sizes, including more than half of the world's top 500 companies. SAP employs
over 23,700 people in more than 50 countries.
SAP has leveraged its extensive experience to deliver the definitive e-business
platform for the new Internet economy – mySAP.com™. The mySAP.com
collaborative e-business platform allows employees, customers, and business
partners to work together successfully – anywhere, anytime. mySAP.com is open
and flexible, supporting databases, applications, operating systems, and
hardware from almost every major vendor.
SAP is listed on several exchanges including the Frankfurt stock exchange and
NYSE under the symbol "SAP."
The technological foundation for SAP collaborative business solutions is the SAP
Internet-Business Framework, which supports a company's ability to create an
agile business software environment that enables fast responses to new business
demands. It provides a comprehensive, scalable platform with which companies
can conduct e-business. Strengths in SAP technology that facilitate interenterprise collaboration and interoperability include an Internet design; more
than 1,500 open interface definitions openly published on the Web; and an open
and flexible component-based architecture. Flexible platform support provides
for high scalability. SAP offers customers world-class reliability and security as
well as the reassurance of accepted industry standards such as the Extensible
Markup Language (XML).
Dell Computer Corporation
Dell Computer Corporation (NASDAQ: DELL) is the world's leading direct
computer systems company, based on revenues of $32 billion for the past four
quarters, and is a premier provider of products and services required for
customers to build their Internet infrastructures. The company ranks No. 48 on
the Fortune 500, No. 154 on the Fortune Global 500 and No. 10 on the Fortune
“most admired” lists of companies. Dell designs, manufactures and customizes
products and services to customer requirements, and offers an extensive
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selection of software and peripherals. Information on Dell and its products can
be obtained at www.dell.com.
Dell Technology Consulting is a group of consulting and implementation
services focused on Dell products, related technologies, and valuable assistance
for the customer’s I.T. environment. They are dedicated to helping the customer
reduce risk, add supplemental resources and become productive more quickly.
Customized engagements can help the customer decide which technologies best
meet the customer’s needs.
Intel Corporation
Intel, one of the world's largest chip makers, is also a leading manufacturer of
computer, networking and communications products. All Dell machines used for
the testing described in this paper used Intel processors. Additional information
about Intel is available at www.intel.com/pressroom.
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