Soas. part i: soa overview

Part I: SOA Overview
1. Executive Overview
Interoperability is one of the key issues facing IT organizations. Service-oriented
Architectures (SOAs) based on Web service standards have emerged as the leading
Industrywide enabler for interoperability.
Companies that are embracing SOAs are finding huge benefits. Some of these benefits
Are expected, such as increased revenue opportunities through collaboration, improved
Decision making through shared data, and decreased personnel costs through automated
Workflow. But many of the benefits of SOAs are unexpected, such as dramatic
Improvements in system reliability, huge reductions in development and deployment
Costs, migration of systems from expensive mainframe to inexpensive server clusters and
Impressive improvements in time to market.
This white paper includes my interviews with companies that are successfully using
SOAs. From these interviews emerged many lessons

that are applicable to any company
Interested in leveraging SOAs.
This white paper also provides a set of criteria for evaluating SOA technologies. I use
ThesecriteriatospecificallyevaluateMicrosoft’sSOAtechnologies, butthesesame
Criteria could be applied to any other SOA vendor. The specific Microsoft strengths that
Emerge from this evaluation are the following:
 Low cost of acquisition
 Tight integration of Web service standards into the programming tools
 A strong collection of enterprise back-end technologies
 Excellent support for interoperability with legacy systems
But this white paper is not about building an SOA with Microsoft. It is about building an
SOA successfully in a heterogeneous environment in which the strengths of many
Platforms can be realized.
2. Overview of White Paper
This white paper is divided into three main parts. Many readers will want to read all three
Parts. Others will want to pick and choose. The three parts are as follows:
 Part I (where you are now) is an overview of service-oriented architectures
(SOAs) and why they are considered so important.
 Part II is a set of case studies that shows how SOAs are used in the real world.
 Part III is an analysis, including lessons learned and an evaluation of the
Microsoft SOA technologies. Many readers will find the evaluation criteria given
In section 9.1 useful for evaluating any SOA platform.2
3. Service-Oriented Architectures (SOAs)
Application interoperability is the single most important issue facing most enterprise
Software architects. The use of SOAs based on Web service technologies is the best
Approach we have to interoperability. This is the message I hear over and over again in
My consulting engagements.
My analysis is backed up by a recent study by Jupiter Research
1
. It showed that when
Choosing a development platform, the top concern of IT decision makers was
Interoperability with existing applications. For 55 percent of the IT decision makers,
SOAP (simple object access protocol) and WSDL (Web service definition language), the
Flagship Web service standards, were the most helpful in solving interoperability issues.
Actually achieving application interoperability is complicated by three factors:
 Most systems were built before SOAs were understood and before any of the Web
Service standards were defined. These systems, therefore, do not support Web
Services.
 Systems run on different hardware and software platforms.
 Systems that must interoperate are often built by different groups and
Communication between these groups is often sparse.



Soas. part i: soa overview