Service Oriented Architecture-SOA

Learn About Service Oriented Architecture (SOA)

What is Service Oriented Architecture?

IT departments are managing increasingly complex IT portfolios. Yet as business needs change,

these departments must still ensure that their technologies remain aligned with business goals.

Failure to do so compromises organizational agility.

The problem for IT departments is typically not insufficient functionality; rather, it is that critical

business systems such as customer relationship management (CRM) and enterprise resource

planning (ERP) operate in isolation from other critical business systems—despite the fact that

business processes often span multiple applications. To obtain an end-to-end view of a complex

business process necessitates integration of information and process silos. In the past, this has

been accomplished either though time-consuming manual interventions, or through hard-coded

solutions that are difficult to maintain.

Service orientation is an approach to organizing distributed IT resources into an integrated

solution that breaks down information silos and maximizes business agility. Service orientation

modularizes IT resources, creating loosely coupled business processes that integrate information

across business systems. Critical to a well-designed service-oriented architecture is producing

business process solutions that are relatively free from the constraints of the underlying IT

infrastructure, because this enables the greater agility that businesses are seeking.

Service Oriented Architecture (SOA) ultimately enables the delivery of a new generation of

dynamic applications (sometimes called composite applications). These applications provide end

users with more accurate and comprehensive information and insight into processes, as well as

the flexibility to access it in the most suitable form and presentation factor, whether through the

Web or through a rich client or mobile device. Dynamic applications are what enable businesses

to improve and automate manual tasks, to realize a consistent view of customers and partner

relations, and to orchestrate business processes that comply with internal mandates and

external regulations. The net result is that these businesses are able to gain the agility

necessary for superior marketplace performance.

SOA defined

Service orientation is a means for integrating across diverse systems. Each IT resource, whether

an application, system, or trading partner, can be accessed as a service. These capabilities are

available through interfaces; complexity arises when service providers differ in their operating

system or communication protocols, resulting in inoperability.

Service orientation uses standard protocols and conventional interfaces—usually Web services—

to facilitate access to business logic and information among diverse services. Specifically, SOA

allows the underlying service capabilities and interfaces to be composed into processes. Each

process is itself a service, one that now offers up a new, aggregated capability. Because each

new process is exposed through a standardized interface, the underlying implementation of the

individual service providers is free to change without impacting how the service is consumed.


Why SOA?

Complex, distributed IT resources are a concern for businesses. Too frequently, the existing IT

portfolio does not adequately meet specific business needs, is costly to manage and maintain,

and is inflexible in the face of business growth and change. The solution, however, is not to rip

and replace systems or applications, nor to completely renovate them, but rather to find a way

to leverage existing IT investments so that overall organizational goals are effectively


Service orientation helps to accomplish these goals by making systems more responsive to

business needs, simpler to develop, and easier to maintain and manage. Implementing a

solution architecture based upon service orientation helps organizations plan ahead for change,

rather than responding reactively.

Who does SOA?

Strictly speaking, SOA is done by developers and solution architects. However, stakeholders in a

service-oriented solution span a range of roles, and it is critical that their interests not only be

taken into account but that they actively drive the design of the SOA solution.

Starting with those interests, the business analyst is concerned with bringing IT investments

more in line with the business strategy. For the developer, this means that the SOA solution

must map the sources of business information—systems, staff, trading partners—into a unified

and comprehensive view such that the business analyst has greater insight into the costs and

benefits of various investments.

The chief technology officer (CTO) of the organization will work with developers to ensure that

when designing a solution to meet the needs of the business analyst, the integrity of existing IT

systems and applications resources are preserved, even as new capabilities are developed.

And the IT manager, concerned with effectively integrating distributed systems such that

management is simplified, will work with the developer to ensure that these goals are also met.

Ultimately, the developers and solution architects are concerned with creating dynamic

collaborative applications that meet the goals of the various stakeholders. The service

orientation approach enables them to do so in a way that meets the needs of the organization

as a whole.

What SOA isn’t

There are numerous misconceptions about what SOA is—that it is a product that can be

purchased (it is not; it is a design philosophy that informs how the solution should be built);

that the goal is to build a SOA (it is not; SOA is a means to an end); or that SOA requires a

complete technological and business process overhaul (it doesn’t; SOA solutions should be

incremental and built on current investments).

SOA is also often equated with Web services, and the terms used interchangeably. While it is

true that SOA is made easier and more pervasive through the broad adoption of Web services–

based standards and protocols, the two are distinct. SOA is an approach to designing systems—

in effect the architectural drawings or blueprint—that directs how IT resources will be integrated

and which services will be exposed for use. In contrast, Web services is an implementation

methodology that uses specific standards and language protocols to execute on a SOA solution.

Before starting a SOA

Before a developer writes a single line of code, it is critical to identify both specific business

drivers of the SOA endeavor and the dependencies between the business and the underlying

technologies. Neglecting the business context can result in a project in which SOA infrastructure

is pursued for its own sake, or where investments are made that do not line up well with the

needs and priorities of the business.

Two approaches are commonly pursued for implementing SOA: top-down and bottom-up. Both

approaches have possible pitfalls that can prevent success. Many organizations that have


attempted to roll out SOA infrastructure through a top-down approach have discovered that

when the infrastructure is finally delivered it is out of sync with the needs of the business.

Likewise, a bottom-up approach can fail as well, because it can lead to a chaotic implementation

of services created without regard to organizational goals.

The “middle-out” approach is a successful hybrid of the two other approaches. Business drivers

and strategic vision are first employed to set clear direction and priorities. Based on these, the

organization takes multiple iterative steps to build out slices of end-to-end capabilities, with

each iteration delivering a new, dynamic application back to the business that is used to create

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