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A Service-Oriented Approach to B2B Integration using Web
Services
White Paper
By
Saumil Gandhi
Published forDREAMSCAPE MEDIA
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TABLE OF CONTENTS
ABSTRACT....................................................................................................................... 3
INTRODUCTION............................................................................................................. 3
STATEMENT OF PROBLEM........................................................................................ 5
SIGNIFICANCE OF THE PROBLEM.......................................................................... 6
PURPOSE OF THE STUDY ........................................................................................... 8
REVIEW OF LITERATURE.......................................................................................... 9
Literature Review Methodology .................................................................................. 9
Resources .................................................................................................................. 10
Important keywords used.......................................................................................... 11LiteratureFindings ..................................................................................................... 12
Issues with existing business integration approaches ............................................... 12
A service (component) oriented approach to developing middleware ..................... 14
Web services for enterprise integration .................................................................... 16
Strengths and Weaknesses ......................................................................................... 18
Definition of Terms ..................................................................................................... 18
Delimitations................................................................................................................ 23
Assumptions................................................................................................................. 24
Limitations ................................................................................................................... 25
PROCEDURES ............................................................................................................... 25
Analyses........................................................................................................................ 28
FINDINGS AND DISCUSSIONS.................................................................................. 29
Evolution of B2B Integration Solutions .................................................................... 29
Theservice of web services - Service-oriented Architecture (SOA) ....................... 32
Benefits of the Service-oriented Architecture for B2B Integration ........................... 36
The web of web services enabling the SOA for B2B Integration ......................... 37
Basic Layers of the Web Service Stack .................................................................... 38
Benefits of web services for B2B Integration............................................................ 40
Web service workflow for B2B integration ............................................................... 42
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Deploying web services the .NET platform ........................................................... 44
Proof-of-concept a web service for credit card validation using .NET............... 46
Prototype Overview .................................................................................................. 47
Credit Card Validation Web Service ........................................................................ 47
Client Applications ................................................................................................... 49
Findings from the proof-of-concept .......................................................................... 50
A web service approach for B2B integration ........................................................... 51
RECOMMENDATIONS FOR FURTHER STUDY ................................................... 54
CONCLUSION ............................................................................................................... 55
REFERENCES................................................................................................................ 59
APPENDIX A .................................................................................................................. 64
creditCardValidatorvb.asmx ..................................................................................... 64
Web Service Description Language for creditCardValidator service ................... 65
APPENDIX B - J2EE client files ................................................................................... 69
input.jsp ....................................................................................................................... 69
JSP result page Result.jsp ....................................................................................... 70
Java proxy class for the web service creditcardvalidatorvbProxy.java ............. 76
Java classes for Soap request object.......................................................................... 79
Java class for SOAP response object ........................................................................ 80APPENDIX C - .NET client ........................................................................................... 82
VB.NET form page ..................................................................................................... 82
The .NET proxy class.................................................................................................. 84
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ABSTRACT
The goal of this study is to propose the usage of a web-based architecture to
interconnect information systems between enterprises. Business-to-business integration
has become a critical issue as organizations find a greater need to consistently interact
with new partners in a global business environment. Some of the problems faced with
earlier integration approaches include scalability, cost of deployment, flexibility and
speed of deployment. The concept of a service-oriented architecture was applied to the
web-based model for B2B integration to help overcome these problems. The author
examined design-level and implementation-level issues in deploying such a web-based
model between enterprises. Microsoft Corporations .NET framework was used to
demonstrate the implementation of a model system for B2B integration. A Proof-of-
Concept was be developed for this purpose, and tested in a simulated test environment to
prove the utility of web services. This prototype simulated an online payment
functionality encapsulated within a web service.
INTRODUCTION
Given the degree of interaction that businesses and organizations have along the
value chain of any industry today, it is critical that these enterprises be able to share
information in a fast, inexpensive, scalable and dynamic way. As stated by Brown,
Durschlag and Hagel, (2002) "The power lies in the ability to make the systems of
trading partners interact."
This understanding has made organizations rethink the way they look at managing
their business processes. Hagel (2002) observes that making connections between
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companies and their applications is highly complex. Traditionally, companies believed in
tightly integrating the processes involved in producing and delivering products or
services, not only within the organization, but across corporate boundaries as well. Hagel
shares two of the biggest drawbacks of doing this. First, these process chains are highly
inflexible because of their close coupling. Second, problems with their suppliers or
manufacturers can be critical and harmful.
To address these concerns, a lightweight coupling architecture and a
corresponding communication platform are needed to allow quick and flexible business
process integration across enterprise boundaries. Organizations could use a framework
that allows them to look at their processes as process networks rather than production
lines (Brown et al, 2002). The termprocess networkimplies a more loosely-coupled
view of business processes, where processes are not tied closely together, and are
relatively independent of each other. With flexible process networks laying the
foundation for business collaboration, organizations can focus on innovation in its core
activities, making these networks more efficient and flexible.
A service-oriented approach supports such a concept, and web services, which
allow services to be offered by specific protocols and communicate over the Internet
provide a distributed computing infrastructure for both intra-and cross-enterprise
application integration and collaboration (Papazoglou and Georgakopolous, 2003).
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STATEMENT OF PROBLEM
A major problem in business-to-business integration is that organizations did not
necessarily agree upon a common communication platform, which constrained the speed
and cost with which key relationships could be established. Medjahed, Boualem,
Bouguettya, Ngu and Elmagarid (2003) mention that initially, technologies like EDI
(Electronic Data Interchange) were used to meet the demand of business-to-business
(B2B) integration. However, as relationships between organizations became more
dynamic in nature, scalability became a big factor in EDI-based integration since it led to
a very high level of coupling between the interacting systems. This and other factors
like cost led to the concept of CORBA (Common Object Request Broker Architecture).
CORBA is a distributed framework which contained independently existing components
that could be used by more than one application by encapsulating them correctly.
Medjahed believes this did not completely resolve scalability issues because it required
the interaction of systems to be restrained by the platforms on which the systems were
deployed.
The above clearly established the need for a common communication platform,
making it easy for companies to share information or interact with other companies easily
and quickly. This need for a common platform led to the choice of the adoption of the
Internet as a communication protocol that all businesses could already access. With the
web as a middleware between interacting objects, information systems can easily form
new relationships with other systems as long as the middleware uses standard and open
protocols that all companies can use and adopt (Stal, 2003). A key requirement in the
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deployment of this middleware is to use an appropriate technology that can fully optimize
the ubiquitous nature of the web for B2B integration.
SIGNIFICANCE OF THE PROBLEM
Two important trends in the business environment today have created the scope
for this study: the ubiquitous adoption of e-business and increasing business collaboration
the exchange of information stimulated by interacting business processes.
The first trend is the widespread adoption of e-business (doing business online),
which Freemantle, Weerawarana and Khalaf (2002) identify as the motivation for
companies to expose their business process over the Web. E-business led to the portal
concept, where a web interface is a one-point entry to the enterprises information
systems. This makes the Internet a critical element in the communication channels
between businesses and between a business and its customers.
The other trend is the need for a business to establish dynamic relationships with
key business partners, suppliers or vendors in an effort to provide end-to-end services to
their customer. Hagel (2002) believes that the long-term value of business collaboration
lies in "mobilizing the assets of partners to deliver more value to their customers." This
consequently requires a greater need for the information systems of the interacting
organizations to be coupled, yet the coupling should be loose enough to handle the
dynamic nature of the relationship.
Web services are an alternative that could combine and optimize the benefits of
these trends. There are a growing number of organizations that have adopted web
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services as an important element in how they do business. Consider the following
statistics:
In a survey of CTOs in 2001 by InfoWorld magazine, 70% of the CTOs
predicted that web services would be most effective in the B2B e-
commerce area of their company.
Andrews (2003) predicts that by 2006, web services will be a
competitive differentiator in business relationships and will be used by
businesses to provide partners with information as easily as possible.
Gartner Dataquest estimates that the worldwide market for consulting
and development and integration services relating to web services
integration software was $7.4 billion in 2002 and will reach $14.3 billion
by 2006 (Cantara, 2003).
According to Varon (2003), in a survey by the Cutter Consortium
consultancy of 250 clients, 13% of the clients said that they were using
web services for business critical applications since January 2003. 54% of
them were developing prototype web services.
These figures are indicators of the significance of web services for B2B
integrations. Frank Moss, chairman and cofounder of Bowstreet, an enterprise portal
provider and a web service user summarizes the significance of web services aptly:
"Companies are transitioning from being product providers to becoming service
providers. To grow their revenue, enterprises have to provide more and more
services around their services products or their existing services. The web services
architecture is a natural way to do that" (Knorr, 2001).
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PURPOSE OF THE STUDY
This study evaluated the implementation of a service-oriented, web-based
technology (e.g. web services) as a middleware platform for integrating enterprise
information systems within organizations or between organizations using open and
scalable standards. It examined the possibility of combining the established and accepted
current practice of a service-oriented application development approach to integration
with a web-based abstraction at an implementation level using contemporary
technologies and platforms.
The purpose of this study was to create and deploy web services on the .NET
framework to demonstrate how systems on different platforms could be integrated. A
prototype web service middleware was created as a Proof-of-Concept (PoC) for this
purpose. The web service was deployed using open and scalable standards (XML and
SOAP). This ensured that an application or a system could invoke this service
independent of that applications deployment platform over the Internet, and
demonstrated the utility of such an approach to facilitate B2B integration.
By analyzing the interoperability of such an implementation, the study illustrated
how a web-based, service-oriented architecture can be used to easily and speedily
integrate disparate business systems with minimal cost and effort. It evaluated this
integration approach from a service-oriented architecture context and judged it on the
basis of parameters like scalability, security, volatility and interoperability.
The .NET framework embraces a range of technologies and development
platforms, allowing it to be viewed as a universal development platform. By proving its
utility in developing web services for the purpose of B2B integration complemented with
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component-oriented architecture, the study provided a reference point for future
implementations of this nature.
The deliverables of this study are:
1. Identification of the parameters for evaluating the service-oriented
architecture as a development approach.
2. A proof-of-concept web service.
3. Demonstration of how an application can invoke this web service independent
of the deployment platform.
4.
Comparison of .NET and J2EE architectures for web services, and the
identification of the benefits of using the .NET framework as a deployment
platform for web services.
REVIEW OF LITERATURE
Literature Review Methodology
The literature review is divided into three sections so as to establish the correct
context for this study.
1. Issues with existing business integration approaches This reviews the history
of B2B integration, and focuses on the problems inherent with some of the
current practices like CORBA and EDI. It provides a context and helps to
understand the present-day solutions to business integration and how they
have evolved to their present form
2. A service (component) oriented approach to developing middleware It is
important that web services be viewed within a certain conceptual framework
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rather than an individual technology or a standalone idea. This has led to the
essential idea behind a successful integration solution a component-based
approach to an enterprise integration solution. This section discusses the use
of components for creating middleware. It explains how the component model
is used in creating a service-oriented architecture for application development.
It then proceeds to demonstrate the utility of a service model for creating
middleware for business integration. This phase thus examines the design
architecture of an integration platform, and suggests how this can be
manifested in a web-based implementation.
3. Web services for enterprise integration This section examines how the
service-oriented approach is applied over the Internet and manifested as web
services. It describes how a web service is better suited for integration over its
predecessors, and discusses the use of widely-accepted protocols like XML
and SOAP. These are the enabling technology elements that contribute
towards making web services a preferred B2B integration solution.
Resources
Gartners research database (which it shares with Purdue University) and online
magazines like CIO.com and ComputerWorld.com were starting points in most research
initiatives. Each of these resources has specific sections related to web services, making
the initial research organized and efficient. Gartner is especially useful in this sense. It
has a series of cross-linked articles that view web services from a service-oriented
architecture perspective, providing greater relevance to this study.
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Technically more involved and detailed resources were needed to scrutinize the
initial cursory research. Industry journals like IEEE and Communications of the ACM are
much more theory-oriented and suitable for researching and developing a theoretical
foundation. Both have considerable resources which discuss the actual implementation
issues and ideas for web services; for solving existing business problems with web
services. Online databases like Academic Elite, Master File Premier and Business Source
Premiere complemented these resources by providing a more real-word manifestation of
the theories and ideas laid out in the aforementioned sources.
Important keywords used
1. Enterprise Resource Planning (ERP)
2. Enterprise Application Integration (EAI)
3. Information systems
4. Cross enterprise integration
5. Business process re-engineering
6. Information flow in enterprises
7. Enterprise information architecture design
8. Web services
9. Service-oriented Architecture (SOA)
10.
XML
11.Middleware
12.Web-based integration
13.Component-oriented software
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14.Component middleware
15.Object-oriented applications
16.Distributed application architecture
17..NET and J2EE architecture
A mix of the above keywords (alone, and in combination with others using the
or and and operators) provided a range of articles relevant to the area of interest.
Literature Findings
Issues with existing business integration approaches
Bill Gates Business @ Speed of Thought (1995) was the first to talk about the
idea of an information backbone for an organization, and stress the importance of an
enterprise information system. Gartner is an excellent resource in terms of current buzz
words related to the topic, and a good predictor of the future of these systems. Comport
(2002) provides an especially useful insight into how the view of enterprise systems
would make a transition from being rigid, closed systems to open architecture systems
using accepted standards. He predicts that through 2007, vendors will shy away from
proprietary application architectures and move towards an open enterprise architecture.
The primary reason for this shift is that the proprietary application architecture does not
allow easy extensions to other systems or applications, since they were not constructed
for this purpose. This is a subtle indication of the fact that Comport feels that businesses
will need to consider the issue of business integration in designing and developing their
information systems, and therefore need to have a strategy that is inherently flexible
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rather than think of a middleware after creating their systems. This is the very basis for a
service-oriented approach.
An important study by Medjahed et al (2003) provides a comprehensive analysis
of business-to-business integration solutions. The study evaluates popular integration
technologies EDI, distributed architecture and XML against factors like coupling,
heterogeneity, adaptability, security and scalability. Coupling refers to the degree of
tightness and duration of interaction between business partners. Heterogeneity refers to
the degree of dissimilarity among business partners, e.g. the difference in data formats
across different information systems. Adaptability refers to the degree to which an
application is able to adapt to changes. Security refers to issues of authentication,
integrity of information, and confidentiality between interacting business partners.
Scalability refers to the ability of a system to grow in one or more dimensions such as
volume of data, number of transactions, or number of relationships managed at a given
time. The study explains how lack of a platform independent middleware has restricted
the utility of EDI or CORBA as an integration solution. It also talks about the important
platforms and notes Microsoft Corporations .NET as an important deployment platform
for future solutions.
A more practical illustration of selecting middleware is illustrated in a case study
by Mondal and Das Gupta (2000). This case study provides insight into the decision-
making process involved in selecting a middleware before adopting a web-based
integration approach of a legacy system. Factors like cost of deployment, scalability of
the system and reusability of the system components are used as evaluation parameters in
ruling out CORBA and similar object-oriented approaches.
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A service (component) oriented approach to developing middleware
Crknovic, Hnich, Jonsson and Kiziltan (2002) examine the formal specifications
of components and component-based relationships. They elaborated on how components
allowed separation of interface from the function, making them important in a distributed
application environment. A paper by Levi and Arsanjani (2002) further stressed the
benefits of adopting a component-based approach to model business information
architecture. Consider the example of a process used to calculate the wages of employees
in a company. Traditionally, this would be encapsulated in a function which is tightly
built into the information system of the company. However, in a component-based
approach, this calculation would be a component that exists independent of the system,
and is called by the system whenever needed, simply by communicating via messages.
Now if the company acquires another business, it would be much easier to adopt a
message-based communication method with a freely existing component, than with a
function hidden within a completely different application. Similar ideas are put forth in
another paper by Sutherland and Heuvel (2002). Both studies indicate that components
can best realize the power of distributed application platforms with a more loosely-
coupled architecture.
Gokhale, Schmidt, Natarajan and Wang (2003) go a step ahead and examine the
application of component middleware in enterprise applications. They propose a specific
middleware approach called Model-Integrated Computing to satisfy demands like
efficiency, scalability, dependability and security in enterprise applications like e-
commerce and automated stock trading systems. This approach involves the abstraction
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of Quality of Service (QoS) specifications rather than establishing them at the
development level. It will help make such services reusable and overcome the limitations
of programming languages when they attempt to achieve those demands. In doing so, it
highlights one of the major advantages that a service-oriented approach has over
traditional integration methods.
The preceding discussion describes the attempts that have been made towards
having a loosely-coupled, component-based approach for business integration. Such an
approach will support reusability in a distributed application environment. It will also
make the middleware more scalable so as to support integration of a greater variety in
applications or systems.
A service-oriented model to implement such an approach was suggested in a
white paper for IBM by Brown, Johnston and Kelly (2003). The paper defines the basic
premise of a service as a software entity that interacts with applications and other
services through a loosely-coupled (often asynchronous) message-based communication
model. The paper discusses how a service-oriented architecture can benefit by using
components for development, and recommends this as a practice for web-based
applications or web services.
A review of the OASIS case study (Bacon and Moody, 2002) brings to the
forefront a practical approach for resolving large-scale interoperation using an open and
distributed service architecture. The study discusses an XML-based version of the Opera
research groups CEA (Cambridge Event Architecture) system which was used in
implementing a health record management system in the UK. The service model was
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used to increase the interoperability of this system and make it independent of interacting
technology platforms.
The idea of software as a service is further explored by Turner, Budgen and
Brereton (2003). The authors proposed a dynamic service model that is aimed at a
flexible and inexpensive way for businesses to interact and perform this interaction over
the Internet.
Web services for enterprise integration
Zarras, Issarny and Kloukinas (2003) discussed the design and development of
middleware for application integration in a distributed system environment. They made a
distinct attempt to approach the integration process keeping the scalability and flexibility
of the solution as a primary concern. Kon, Costa, Blair and Campbell (2002) presented a
study on a model for designing next-generation middleware: reflective middleware. The
model was designed with the view of supporting distributed development for web-based
applications, again as a means to achieve easily scalable and dynamically manageable
enterprise integration solutions.
Stal (2002) proposed using web-based lightweight protocols like XML, HTTP
and SOAP to encapsulate the integration solution in a service-oriented architecture. The
paper made the case of employing the Internet as it was the single most uniform and
accepted communication protocol across enterprises and industries. Stal states that he
objective is to master and manage the heterogeneity, not eliminate it.
XML is the building block for creating any web service. Any business integration
has data exchange as one of the core objective. Stackpole (2001) feels that XML is likely
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to become the standard for automating data exchange between business systems, whether
between systems in one company or between suppliers and customers. Scribner and
Stiver (2002) consider two important reasons for the widespread use of XML. First, it is
loosely-coupled, which means sending an XML document is like sending text rather than
formatting data in a proprietary protocol. They feel that this is a key reason for its wide
acceptance on the Internet. Second, because it is used on every computing platform, its
interoperability is very high.
One of the main reasons for Microsoft developing the .NET platform was to take
advantage of the concept of web services. Web services are built, from a developers
perspective, with the modular development technique. To take advantage of this,
Microsoft incorporated two key concepts in the .NET approach for modular architectures,
as discussed by Weiss (2001). One is that an application is not restricted to a single
computer. Rather, it is envisioned as being constructed of services invoked over a
network. The second is the language independence it offers when it comes to code
reusability. This involves the usage of SOAP as a standard communication protocol
between interacting web services. As long as SOAP is used, web services on a .NET
platform can be developed using any language and will still be able to interact with each
other.
Knorr (2003) explains that web services will play an important role in business
integration because they will help make applications inside the enterprise available to
other applications by wrapping them in web service interfaces. As organizations
standardize their internal systems and interfaces, web services will take them closer to the
plug-and-play integration environment.
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Strengths and Weaknesses
The reviewed literature establishes a solid foundation for the need of a new
middleware approach to business integration. A major strength of this new approach is
that the pitfalls in the earlier middleware approaches have been clearly identified, thus
delineating the scope of what is needed to be done in proposing a better solution.
In the context of this project, a major weakness in most of the current bodies of
knowledge reviewed by the author is that they propose only models or theories describing
the application of service-oriented architectures for business-to-business integration. The
actual implementation has not been discussed at the same level of detail. Though other
papers have further described how a web-based model for such an approach would serve
the needs of managing dynamic and flexible business relationships in a scalable fashion,
they do not describe how to make the transition from the model to the actual application.
The strength of this study is that it probed deeper into the actual implementation
of the proposed web-based model. The study identified the design and development-level
issues of such an implementation. It used Microsoft Corporations .NET deployment
platform for Web Services to develop the web-based integration model within service-
oriented architectures, and identified the benefits and problems inherent in such an
approach.
Definition of Terms
.NET Architecture - The infrastructure of the .NET platform from Microsoft. It includes
the Common Language Runtime (CLR) and .NET Framework class library. The
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CLR provides the environment for running .NET applications, and the class
library provides the foundation services, including ASP.NET, ADO.NET,
Windows Forms (for building GUIs) as well as classes for accessing COM
services
B2B see Business to Business
Business process In context of information systems, a it is the application of a business
transaction to a database.
Business to Business Integration Refers to application integration across companies
for the purpose of exchange of products, services, or information between
businesses rather than between businesses and consumers.
Business Process Re-engineering - Using information technology to improve
performance and cut costs. Its main premise is to examine the goals of an
organization and to redesign work and business processes from the ground up
rather than simply automate existing tasks and functions.
Component Middleware Refers to middleware that consists of program modules that
are designed to interoperate with each other at runtime. Components can be large
or small. They can be written by different programmers using different
development environments and they may or may not be platform independent
Component-Oriented Software - Program modules that are designed to interoperate
with each other at runtime. Components can be large or small. They can be
written by different programmers using different development environments, and
they may or may not be platform independent. Components can be run in stand-
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alone machines, on a LAN, intranet or the Internet. Examples of this include
J2EE, .NET, CORBA, DCOM.
CORBA (Common Object Request Broker Architecture) - A standard from the
Object Management Group (OMG) for communicating between distributed
objects (objects are self-contained software modules). CORBA provides a way to
execute programs (objects) written in different programming languages running
on different platforms no matter where they reside in the network.
Coupling Architecture the assembly of software components, technologies and
protocols that bind disparate information systems together for the purpose of
exchanging or sharing information.
Cross enterprise integration see business to business integration.
CTO (ChiefTechnical Officer) The executive responsible for the technical direction of
an organization.
DCOM - (Distributed Component Object Model) Formerly Network OLE, it is
Microsoft's technology for distributed objects. DCOM is based on COM,
Microsoft's component software architecture. It defines remote procedure calls
that allow objects to run over a network.
Distributed application architecture A highly modularized software system whose
functions are represented by components that are logically independent of each
other. The system relies on interaction between different components to
accomplish its task.
Enterprise Application Integration - Refers to integrating applications internally within
the organization in contrast to business-to-business (B2B) integration.
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EDI (Electronic Data Interchange) - The electronic communication of business
transactions, such as orders, confirmations and invoices, between organizations.
Third parties provide EDI services that enable organizations with different
equipment to connect. Although interactive access may be a part of it, EDI
implies direct computer-to-computer transactions into vendors' databases and
ordering systems.
Enterprise Information Systems/Architecture A computer-based information
backbone of an organization that is responsible for collecting, managing and
disseminating business information within and across enterprise boundaries
ERP (Enterprise Resource Planning) - An integrated information system that serves all
departments within an enterprise
Information flow refers to the path that specific data follows from beginning to end
within an information system
Information system - A business application of the computer. It is made up of the
database, application programs, manual and machine procedures and encompasses
the computer systems that do the processing
Internet - is made up of computers in more than 100 countries covering commercial,
academic and government endeavors. Originally developed for the U.S. military,
the Internet became widely used for academic and commercial research. Users
had access to unpublished data and journals on a huge variety of subjects. Today,
the Internet has become commercialized into a worldwide information highway,
providing information on every subject known to humankind.
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J2EE - A platform from Sun for building distributed enterprise applications. J2EE
services are performed in the middle tier between the user's machine and the
enterprise's databases and legacy information systems. J2EE comprises a
specification, reference implementation and set of testing suites
Legacy Application or System - An application that has been in existence for some
time. It often refers to mainframe and ERP applications; however, as users
abandoned DOS and Windows 3.1 for Windows 95/98 and NT, they too are
called legacy applications
Middleware Software that manages interaction between disparate applications and
platforms; a computer intermediary.
Service-oriented Architecture A software framework in which software components
are exposed as services on the network and can be reused for different
applications and for different purposes.
SOAP (Simple Object Access Protocol) - A message-based protocol based on XML for
accessing services on the Web. Initiated by Microsoft, IBM and others, it employs
XML syntax to send text commands across the Internet using HTTP
UDDI- (Universal Description, Discovery and Integration) An industry initiative for a
universal business registry (catalog) of Web services
Value Chain The sequence of business partners along any industries that interact with
each other to provide a service or a product to the customer.
Web-based architecture Refers to software that runs on or interacts with a Web site,
which may be on the Internet or on an in-house intranet.
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Web-based integration Refers to integration software that runs on or interacts with a
Web site, which may be on the Internet or on an in-house intranet
Web Services - Web-based applications that dynamically interact with other Web
applications using open standards such as XML, UDDI and SOAP. These
applications typically run behind the scenes, one program "talking to" another
(server to server). Microsoft's .NET and Sun's Sun ONE (J2EE) are the major
development platforms that natively support these standards
WSDL-(Web Services Description Language) A protocol for a Web service to describe
its capabilities. Co-developed by Microsoft and IBM, WSDL describes the
protocols and formats used by the service.
WSFL-WSFL (Web Services Flow Language) is a protocol from IBM for describing the
workflow between services.
XML - XML (Extensible Markup Language) is an open standard from the W3C for
describing data. XML provides a flexible way to create common information
formats and share both the format and the data on the World Wide Web, intranets,
and elsewhere. The developer, depending upon the business requirement, can
define XML tags.
Delimitations
The study did not explore the underlying concept of component-based
architecture in detail. It primarily investigated the web-based model that can be built on
top of it.
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The purpose of the study was to focus on the implementation of web services
using .NET. Although XML and SOAP were used to create the web service, this study
did not explore the benefits and drawbacks of these technologies the purpose was to
study system interoperability rather than data exchange. In this context, the possible
issues concerning the implementing of these technologies was not be the focus of this
study.
The evaluation of web services using the parameters identified during the
literature survey was a qualitative one. This evaluation was in the form of a comparative
analysis of web services with other integration techniques, rather than a direct measure of
the parameters. The selection of the comparative analysis was due to both the lack of
established methods or measures for assessing web services and the need to limit project
scope. Creating the metrics and a framework to apply them for measuring these
parameters would have exceeded the scope of this study.
Assumptions
The study assumed that web-based standards for web services, though not
universal, are considered widely used enough within the industries that will implement
web services to support the claim of web services being scalable and platform
independent.
The study further assumed that participating businesses have their information
systems designed and implemented using the accepted distributed application architecture
using a component-oriented approach.
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Limitations
The development and publishing of a full-fledged web service that would meet
the needs of businesses would have taken significantly more time than was available for
this study. As such, only a basic web service was created. Similarly, only a simulation of
a B2B environment was possible. Testing of the web service in a live environment was
not feasible. This would have required publishing of the web services on a public server,
and registering the web services with a public registry. The cost associated with the
above two activities and the technical support available for the scope of this study
restricted the testing to a simulated environment.
PROCEDURES
The study was a qualitative analysis of technology factors in business-to-business
integration. The objective of the study was to analyze an implementation of web services
on the .NET platform and evaluate the web services that were developed as a B2B
integration mechanism against parameters mentioned by Medjahed et al (2003). These
include scalability, security, heterogeneity and adaptability. As explained in the
delimitations section, the study did not entail measurement of specific metrics for these
parameters, but relied on a more qualitative approach.
The target population is any two or more business information systems interacting
via a middleware tool. Although the interacting systems can be deployed on any
platform, there is a stipulation that they must support the concept of a distributed
computing architecture to enable a web service integration solution. For the scope of this
study, the sample business information systems were simulated using specific
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components of the whole system. A web service was the interface between these two
application components.
The study consisted of four distinct phases:
1. Examination of existing B2B integration techniques.
2. Analyses of the service-oriented architecture and its benefits in B2B
integration.
3. Analyses of web services from a service-oriented architecture perspective and
its suitability for implementing a B2B integration solution.
4.
Developing a web service proof-of-concept using the.NET platform.
The study attempted to provide a historical perspective in the continuing issues
that have hindered business communication. Broad categories like industry standards,
communication protocols and technology platforms were investigated to identify
implementation level issues for business integration. Identifying problems from this
initial research, the study proposed a possible solution applying a service-oriented
approach for a web-based model as an alternative method to integrate disparate
information systems. A model web service was created on Microsoft Corporations .NET
platform and used as a prototype to understand and illustrate the possible benefits and
drawbacks of using this approach for resolving the issue stated above.
The study relied on the sources identified during the literature review to present
the evolution of business-to-business integration to its current form. This analysis
involved papers on each of the earlier integration solutions to provide a complete
perspective on these solutions. Discussions of the underlying technology led to the
problems inherent in these solutions. Medjahed et al provided one such discussion and
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comparison of earlier business integration solutions (EDI, component based integration)
and provided an insight into the need for a web-based, service-oriented architecture. The
study analyzed the literature to provide a summarized report of previous technologies and
their problems.
Articles and case studies from leading publications like IEEE, ACM and
resources like Gartner Research established the importance of a service-oriented
approach for integration in todays business environment. The resources in this phase
were analyzed more critically, keeping in mind the important factors that in the first place
led to the recognition of such an approach scalability to provide for a more dynamic
and flexible business communication infrastructure between enterprises.
The study then provided a more technology-related perspective of this proposed
solution. It explored the relationship of the needs and characteristics of a service-oriented
approach to business integration, and how these could be complemented by implementing
such a solution using Microsoft Corporations .NET development framework on a web-
based model (Web Services). An important goal was to substantiate the reasons for using
.NET as a development framework for creating web services for business
communication. By comparing broad-level features of this environment with other
leading technology frameworks like J2EE, the study also provided a comparative
rationale for using .NET.
A model web service was developed adopting a service-oriented development
architecture (Plummer, 2003) to simulate and demonstrate how independent businesses
could interoperate via this web service. This web service was developed and deployed
using the .NET platform. XML was used as the data format and SOAP as the
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communication protocol as both these technologies are considered to be industry
standards. For the purpose of this study, an online credit card approval service was
created. By demonstrating that systems on different technology platforms (like .NET and
J2EE) could access and use this web service, the study demonstrated the interoperability
of web services. This proof-of-concept was used to identify two distinctive elements of
web services that make it a B2B integration technology - namely its usage of SOAP and
the concept of WSDL and proxy class and how they helped make web service a better
approach to B2B integration. These findings were the basis in developing the web service
approach to B2B integration.
Analysis
An online credit card approval component-based system is the proof-of-concept
that was developed for this study. It was designed and deployed following the principles
of a distributed, component-oriented approach. Important guidelines and ideas for this
development were discussed by Issarny, Kloukinas and Zarras (2003) and Brown et al
(2003). Further, the ideas proposed by Turner et al (2003) to orchestrate these
components and treat the software as a service was the key in designing the web service.
to the web service was created to be highly re-configurable to allow deployment over the
Internet using standards like HTTP and XML. Microsoft Corporations .NET platform
was used as the deployment platform.
The study analyzed the following
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1. The implementation of a web service using the .NET framework this
identified the benefits and drawbacks of deploying the web service on the
.NET platform.
2. The implication of adopting the service as a web-based interface for different
applications to communicate with each other this investigated how factors
like scalability, adaptability and cost of implementation were affected by the
approach this study recommends.
FINDINGS AND DISCUSSIONS
This section of the report includes the following:
1. Identifies the issues and challenges in B2B integration.
2. Demonstrates how SOA would serve as a conceptual solution to these
problems.
3. Explains how web services will manifest SOA in creating a B2B integration
solution at a practical level.
4. Identifies the benefits of deploying such a web service solution on the .NET
platform using a proof-of-concept web service.
5. Uses the proof-of-concept as a basis to develop a web service approach for
B2B integration
Evolution of B2B Integration Solutions
The challenge in B2B interaction lies in the integration and interoperation of both
application and data (Medjahed et al, 2003). This is due to the heterogeneous systems,
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distributed applications and legacy data formats that every business has maintained. They
identified the following dimensions to evaluate a B2B integration framework: coupling
among partners, heterogeneity, autonomy, external manageability, adaptability, security
and scalability. Samtani and Sadhwani (2002) put forth a similar set of parameters
required from a B2B integration solution. The solution should automate real-time
exchange of data between disparate applications of any business partner at any point in
time (coupling). The solution should also provide for monitoring services like log audits
and secure transactions (security, external manageability). The solution should be able to
support different data formats and communication protocols that each of the interacting
business use (heterogeneity). The solution should be deployed on a global set of
standards that allow any business to use it (autonomy). And finally, the system should be
scalable vertically and horizontally (scalability). All these issues had to be considered at a
practical level in the following B2B connections:
1. Front-end with back-end systems
2. Proprietary/legacy data sources, applications, processes and workflows to the
web
3. Trading partners systems
Initial B2B efforts to resolve the above problems resulted in the creation of
Electronic Data Interchange (EDI) (Accredited Standards Committee , 2004). EDI is the
inter-organizational application-to-application exchange of standardized business
documents between computers. EDI defines a limited set of document formats based on
the ANSI X12 standard. The main objective of these documents was to represent the
business transactions electronically and eliminate paper-based transactions more than
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providing an interacting platform for B2B communications. As such, EDI did not
consider a lot of factors relevant to B2B integration. EDI provided a very strongly-
coupled environment, leaving no flexibility for partners who did not follow the EDI
standards. Also the cost of joining an EDI network was considerably high as it involved
proprietary and expensive networks. This constrained the scalability and autonomy of
EDI as a B2B integration solution. In terms of B2B connections, EDI was primarily setup
only for trading with partners systems. It was not used for connecting front-end with
back-end systems or for exposing proprietary systems and workflows to the web.
To facilitate a more flexible interaction between businesses, the component
middleware framework was conceived. Component-based systems consist of a
lightweight kernel to which new features can be added in the form of components
(Bichler, Segev and Zhao, 1998). A component is defined as a self-contained entity that
describes and/or performs a specific function. This approach requires interconnection of
geographically-distributed components and allows interoperability between components
of different systems. CORBA, DCOM and EJB are examples of component middleware
frameworks. However, when it comes to inter-organizational B2B interactions,
component-based interaction is limited by the fact that the interacting systems need to be
deployed on the same platform. A CORBA-based component (deployed on Java) cannot
communicate with a DCOM component (deployed on Microsofts component software
architecture). This greatly limits the scalability and adaptability of these frameworks.
Component-based systems also result in tightly-coupled business systems, and do not
adapt to rapid changes in business processes and new business partners. Like EDI, it had
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no inherent support for exposing systems to the Internet to allow easy and quick access to
business information for their partners and customers.
The preceding analysis clearly highlights the drawbacks of contemporary
middleware techniques. This project suggests the use of a different integration method
based on the service-oriented architecture to overcome these problems. Before
identifying the benefits of this technique, it is important to understand the architecture
itself. The advantages that web services hold over other contemporary B2B technologies
are best described by the two components that make up its name web and services.
Theservice of web services - Service-oriented Architecture (SOA)
The service component of web services refers to the conceptual idea behind web
services. Web services are constructed on a service-oriented architecture (SOA). The
basic (technical) concept underlying this architecture is to provide access to software
functionality by wrapping it as a service. Service here is defined as a unit of functionality
with its semantics defined in the form of an interface Perrey and Lycett (2003). This
implies a dynamic application structure. Unlike a distributed application which consists
of software functionality wrapped as objects bound to each other the service-oriented
application environment consists of a loosely-coupled service space. If the user of a
service-based application desires a particular functionality, the application will invoke the
correct service from this service space. In essence, the service-oriented architecture turns
software into a service by enabling the dynamic creation of one or more services or
functionality using existing services. This objective is achieved by a process called ultra-
late binding (Turner et al, 2003).
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Ultra-late binding allows the services in the service space to exist independently
of each other; they are coupled only when one service needs another to perform a task.
The software as a service paradigm (Turner et al, 2003) differs radically from the
traditional software development approach in that it envisions the service model to be
demand led; applications can be constructed from smaller component services and
bound dynamically as needed. This is called service composition. Traditionally,
software components were packaged together to serve a pre-determined set of purposes,
and could not be repackaged to perform other functions if needed. With the introduction
of the concept of service composition, SOA allows binding of lower level services to
create a new service which can be used without user intervention as the business need
and context change.
It is necessary to understand the general framework and elements of the SOA that
contribute to its feasibility as a B2B integration framework. Figure 1 is a simplistic view
of a working model of a SOA.
Figure 1. The Service Model. Source: www.ibm.com
Each element of the SOA can play one or more of the three roles service
requester, service provider, and service broker (Tsalgatidou and Pilioura, 2002). Service
provider is the entity that provides the software application or functionality as a service.
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The provider is considered to be the owner of the service and the platform where it is
executed. The service broker registers and categorizes services to make them searchable.
Service providers publish their service with the broker. The service requester is the
system (or business) that needs the software functionality. The requester will search for a
service from the service broker. Once a service has been found, the service provider for
that service will bind the service request from the requester (ultra-late binding) and the
necessary functionality will be provided to the requester.
The interactions between these three roles are driven by three primary actions
service description, service discovery, and service delivery (Turner et al, 2003). Service
description is the most important function in SOA it is what is published, requested and
categorized for every service (Burbeck, 2000). The service description makes it possible
for the service provider to describe the syntax and semantics of the service so that the
service can be mapped to fulfill a client need. The service description includes
descriptions of functionality, interfaces, and nonfunctional characteristics like security,
authentication and privacy issues related to the exchange of information and constraints
such as quality of service and cost. This description is published with the service broker.
A business or client (i.e. a service requester) can use service discovery to identify which
service will meet the organizations functional requirements. The service description of
that service is used to make this assessment. Service discovery also include service
negotiation, which is used to create an agreement between the service provider and
requester. Once the requester has identified the correct service from the service discovery
phase, the provider will deliver the service to the requester. This is the service delivery
phase, or the runtime phase. It is when the sequence of collaborations between services is
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realized. It requires the calling client/interface to invoke the correct service based on the
agreement created in the service discovery phase. The provider will then provide the
service in a manner and for a period of time as agreed upon in the contract with the
requester via service binding. This sequence of events between the three roles constitutes
the actual functionality of the service-oriented architecture.
A more complete environment for implementing the service-oriented architecture
would involve non-functional services like monitoring and quality of services, value-
added services, security and monitoring. An extended service-oriented architecture which
encompasses this is shown in Figure 2, and would be a more practical representation of
the SOA.
Figure 2. Extended Service-Oriented Architecture. Source: Communications of the ACM
The relevance of a service-oriented architecture for B2B integration One of the
objectives of this project was to clearly understand how this technical concept of services
is relevant when considering B2B integration at the process level. Perrey and Lycett
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(2003) define services from a business perspective as a unit of transaction described in a
contract and fulfilled by the business infrastructure. The presumptions and semantics of
service signify the business experience and this shapes the perspective. The benefit of
the service-oriented architecture then stems from the fact that it provides an architecture
for organizing a technical framework which will support the automation of business
services and processes to permit restructuring to serve the demands of new or constantly
changing processes. In the context of B2B integration, this implies having a central
network of independently existing services whose interfaces define the semantics, syntax
and functionality of the service. When an inter-organizational process has to be executed,
the predefined workflow for that process will compose the required services from the
service space, choreograph the sequence of execution of the services and orchestrate the
business process in the service-orientation architecture. Thus, stateless services are
composed and choreographed based on the context provided by the workflow that is
defined by the business process at the time of execution of the process.
Benefits of the Service-oriented Architecture for B2B Integration - The most
obvious benefit of SOA over EDI and component-based integration is that it provides a
loosely-coupled integration framework. SOA focuses on delivering functionality as a set
of distributed services that can be configured and bound at execution time (Turner et al,
2003). This ultra-late binding of services makes it much more flexible and adaptable to
accommodate new services (or functionalities). Thus the scalability of such an approach
is much more than previous B2B integration techniques. Again, because services are not
bound to each other until needed, different systems built on a similar architecture can
access an existing service or integrate their service with one from another system by
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simply invoking it (assuming that the security policy allows it to). The interaction of
these services is independent of the deployment platform. This independence means that
the interoperability of the SOA solution will be much higher. SOA is most popularly
manifested in web services (Papagozlou and Georgakoplous, 2003). It involved the usage
of standard protocols like SOAP and XML for messaging and storing data, which have
been accepted as standards for web services by most leading web service platforms
including IBMs Web Sphere, Microsofts .NET and Suns J2EE. This makes SOA a
heterogeneous and open architecture to deploy middleware integration solutions. SOA is
also extensible, allowing participating businesses to adopt their own data formats using
XML and still be able to engage web services for B2B interactions. Thus, SOA supports
all three B2B connections mentioned above front-end to back-end, legacy systems
exposed to the web, and between trading partners system.
The web of web services enabling the SOA for B2B Integration
The web component of web services refers to the practical or implementation
aspect behind the concept of web services. Web services can be defined as self-contained,
modular applications, accessible via the Web, that provide a set of functionalities to
businesses or individuals (Tsalgatidou and Pilioura, 2002). Software applications
developed on a service-oriented architecture are manifested on the Internet as web
services. The Web has become the user interface of global business, and web services
now offer a strong foundation for software interoperability (Chung, Lin and Mathieu,
2003). Companies are exposing their business processes and systems on the Internet to
achieve greater automation, efficiency and global visibility. Web services allow
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companies to do this using the SOA described in the previous section. Because they
allow businesses to take advantage of the loosely-coupled application paradigm of SOA
over the Internet, it makes web services important for B2B integration. A brief
understanding of the architectural elements of web services can be instructive before
realizing how web services as a whole are relevant to B2B integration. These elements
include protocols and standards that allow system developers to develop service-oriented
applications over the Internet, non-functional characteristics like security, quality of
service and workflow management, and application programming interfaces (APIs) that
allow individuals and businesses to locate and utilize web services. These elements are
thus the enabling tools of SOA for application development. The elements put together in
an architectural framework are referred to as the Web Services Stack. A general view of
the stack accepted as a standard by all leading web service vendors is in Figure 3:
Figure 3. The Web Services Stack. Source: IBM Journal
Basic Layers of the Web Service Stack
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o The network is the underlying transport protocol layer which makes web
services available over a network. The stack supports the HTTP protocol
which allows access to web services via the Internet, and also other important
network protocols like SMTP, FTP, IIOP and MQSeries. In its truest form,
messaging in web services is independent of the protocol used at the network
layer. This freedom from being tied to a specific protocol ensures that web
services do not end up being a proprietary tool, which is very important for a
B2B interaction. Again, its support of the HTTP protocol implies that any
business that can access the Internet would be able to participate in a web
service-based business interaction.
o Over the network layer is the XML messaging layer. It uses the Simple Object
Access Protocol (SOAP). SOAP is a standard for messaging and making
remote procedure calls over the Internet between the service requester and the
service provider. It is independent of the transport protocol or the
programming language of the requester or the provider. It is essentially an
XML document coded in a specific format. SOAP messages are used to
publish, find, bind and invoke services. The SOAP document consists of three
sections. The envelope contains the namespace information for that message.
The headis used to encode information regarding non-functional services like
authentication and security. The body contains the main message
o Web Service Description Language (WSDL) is used for describing the web
service. This is also an XML-based schema used to describe the functionality
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of a service in terms of its interface. It also contains information regarding the
location of the service and how to invoke it.
o The Universal Description, Discovery and Integration (UDDI) protocol is an
XML-based schema used to publish web services. Publishing allows a
business requiring a service to gain access to the WSDL document of a
service to determine if the service matches the business need.
Since web services are a realization of the SOA, the roles and interactions in a
web service environment will resemble the interactions shown in Figure 4.
Figure 4. Web service interactions. Source: Distributed and Parallel Database
Benefits of web services for B2B Integration - This project identifies the use of
XML (Extended Markup Language) as one key factor that makes web services a
potentially universal option for B2B interaction (besides its foundation of SOA). Major
standards in web services like WSDL, UDDI and SOAP are all XML-based protocols.
This stems from the fact that XML is not merely a data format but is more of an open
standard which can be used to represent any data as needed by a business. In the case of
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data storage, when XML is used for storing information, interoperability between
systems can be achieved since one XML representation can easily be converted to
another. Because web services employs XML as its native protocol (irrespective of the
deployment platform), web services deployment and accessibility is not restricted to any
technology, platform or vendor, and it makes web services a superior candidate for B2B
integration.
The benefits of adopting web services as an integration technique are latent in its
architecture. The protocols at every layer of the stack are XML based, which is accepted
as the standard in interoperability by all major businesses in the B2B community. This
standardization of the open protocols and APIs shown in Figure 3 is the key to the
ubiquitous deployment of the web service architecture, and the ubiquitous deployment of
the infrastructure is the key to the adoption of web services (Gottschalk, Graham,
Kreger and Snell, 2002). Systems using XML can interact with each other even if the
XML encoding is different for each system. The deployment platforms of systems or
their geographical location does not impact the interaction as long as both systems can
access the Internet. This is a great advantage that web services hold over traditional B2B
integration methods, all of which were tightly-coupled and platform-dependent. Thus, at
the data level, system interoperability is achieved using web services. The benefits of the
web services stack for B2B interaction are summarized by Baglietto, Maresca, Pardoi and
Zingirian (2002) below:
1. Integration of enterprise systems and collaboration using Internet wide
transport protocols (HTTP/SMTP).
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2. Interoperability achieved by exploiting XML formats for document exchange
and service access through SOAP protocol.
3. Registry-centric, distributed architecture adopting the UDDI Registry
standard.
Web service workflow for B2B integration - B2B interactions are not limited to
data exchange. It is the inter-organizational interoperability that can be achieved at the
process level using web services that makes it a superior approach to B2B integration
compared to previous attempts. This project introduces the notion of using web services
at a process level using a concept called workflow of web services. Implementing and
managing web service workflows across organizational boundaries would lead to B2B
interoperability. B2B integration through workflows requires the construction of business
processes from multiple web services. This is referred to as web services composition. It
requires mapping a business process to one or more web services and controlling the flow
of these web services to execute the process. It is driven by two activities orchestration
and choreography, as depicted in Figure 5.
Figure 5. Orchestration and Choreography of Web Services. Source: IEEE Computer
Society
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Peltz (2003) defines orchestration as an executable business process that can
interact with both internal and external web services. The interactions occur at the
message level. They include business logic and task execution order, and they can span
applications and organizations to define a long-lived, transactional, multi-step process
model. Choreography is associated with tracking messages among the interacting
services across organizations, and is required to maintain the overall state and context of
the orchestration process.
Interoperability at the process level to enable such an orchestration of services
requires the representation of business processes as web services. This mapping of a
business process to a web service can be accomplished by the Business Process
Execution Language (BPEL). It is one of the specifications for representing process
workflows, and has support from Microsoft, IBM, Siebel and other major web service
vendors. Leymann, Roller and Schmidt (2002) propose an approach to implement
activities within a business process using web services. It uses directed graphs to
implement flow models a graphical representation of processes. Once the activities in a
process have been identified in the flow model, BPEL (or a similar language) can be used
to model each activity. Both interacting partners need to adopt this approach before true
B2B integration can be achieved. In a true service-oriented architecture, the interacting
business partners will expose the service interfaces of inter-organizational processes as
WSDL descriptions. When interaction is required, the BPEL (also an XML-based schema
like WSDL) representation of the process will use the WSDL ports of each partner to
facilitate the execution of the process across the organizations.
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The author feels that as business interactions exceed the traditional boundaries of
information exchange and extend to process interoperability between partners and
vendors to leverage the true power of business automation and derive maximum
efficiency, the application of workflow technology to web services for B2B interactions
will be the single most important factor in creating a successful business integrating
approach. This could potentially be the greatest benefit of web services when used for
B2B integration.
Deploying web services the .NET platform
Microsoft's .NET framework and Sun's J2EE (Java2 Enterprise Environment) are
the two industry leaders in providing platforms for web services. Though both have, for
the first time, agreed on the core standards that define web services, both have distinct
and often contrasting approaches to deliver the benefits of web services to customers.
The basic premise of the argument is that the .NET framework can better leverage
an existing Windows environment. .NET is tightly coupled with the Windows operating
system. It provides for better integration of web services with other Microsoft products.
This is primarily because the .NET framework was architected around XML and web
services. It is not as mature, so existing Microsoft applications need to be recoded to
move them to .NET. J2EE enables a more cross-platform solution. It is not a product
suite like .NET, and is more of a standard that developers and applications need to follow
to fall within the J2EE framework. As such, J2EE provides a more abstract and loosely-
integrated environment. J2EE uses Java, which is more mature; however, its vendors
view web services as more of an add-on to a proven technology.
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.NET is accepted as the early mover in web services. More importantly, it can
boast of a framework developed with web services as the core idea. Weiss (2000) pointed
out that the core idea in conceiving the .NET framework was that of providing a
distributed computing environment. The .NET framework views an application as
fragments of functionality spread over a network. This loosely-coupled approach to
application development is synonymous with the service-oriented architecture
philosophy, and as such the .NET architecture and its elements inherently support the
deployment of web services for B2B integration.
.NET provides intrinsic support for the main elements of web services XML.
.NET also supports messaging via the HTTP protocol. These factors make .NET an
important alternative. The .NET environment has intrinsic support for web services in its
major components the .NET framework, Visual Studio.NET (VS.NET) and ASP.NET
(Newcomer, 2002). .NET also hosts the client and server technologies for web services,
which J2EE does not. This implies that if a .NET application wants to expose a service or
functionality as a web service, it is one of the native options available in VS.NET. In the
case of J2EE, an additional step of wrapping the service in a certain type (called
Enterprise Java Bean or EJB) is needed before it can be exposed as a web service. Thus,
every web service feature or standard (like SOAP or WSDL) requires the use of
additional APIs with the J2EE framework, while .NET has support for this built into the
platform itself.
Another benefit of using the .NET platform is the sophisticated IDE available for
developing web service applications Microsofts VS.NET (Visual Studio.NET).
Because J2EE is a standard and not a platform, there is no one integrated IDE that can
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provide the development support for web services as easily as VS.NET does. The
relatively friendlier user interface and proximity with the .NET framework make
VS.NET a preferred IDE for web service developers. .NET does have a drawback in that
it is tied to the Windows platform, as it has evolved from the Windows DNA
architecture. Thus, a .NET developed web service needs to be hosted on a Windows
server, limiting its deployment scope to a Windows environment. However, the
interoperability of the web service thus developed is not affected, and as such is still a
widely used development platform for web services.
Proof-of-concept a web service for credit card validation using .NET
A prototype web service was created for this project. This was the proof-of-
concept required to demonstrate the utility of web services for business integration. The
proof-of-concept was also developed to demonstrate the deployment issues that arise in a
practical case scenario of implementing web services. Microsofts .NET framework was
the chosen deployment platform for the proof-of-concept, and enabled a first-hand look at
the benefits and problems faced in using .NET for creating and deploying web services.
.NET provides a way for mapping class methods or functions to a web service.
One of the most efficient and popular ways to do this is using the WebMethods
framework in ASP.NET. Conceptually, web services involve processing of SOAP
documents, which are messages requesting a certain operation and encoded in XML.
WebMethods provides an abstraction to this messaging by generating and parsing the
SOAP documents that are sent from and received by the web service. Thus developers
need not understand the XML schemas used for SOAP messages while creating or
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invoking web services. A class representing the web service is created, and the
functionality that it will provide is encapsulated within the methods of this class.
Prototype Overview- The prototype consists of a client requiring credit card
validation for any user filling out his/her credit card details and submitting the form. This
client could be a desktop application or an e-commerce web page. The client platform
could also be variable. A .NET application which provides this validation service using
Luhns Formula was created using Visual Studio.NET and deployed on an IIS server
(Internet Information Server) with support for the .NET framework. To achieve
interoperability with any operating system, this application was conceived, developed and
exposed as a web service, and made accessible over the Internet. Two clients were
created, one a desktop application form on Microsofts .NET platform using VB.NET
(Visual Basic.NET) and the other on Suns J2EE platform using JSP (Java Server Pages).
The use of a desktop application created on one platform and a web application on
another platform to call a web service clearly indicates the extent of interoperability that
can be achieved using web services. An attempt was made to