Few things about SOA

What is SOA?

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.

What SOA is not?

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. That meanse there are services which are not webservice based, but SOA oriented. There are alos Services, which are webservice based not not SOA oriented. 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.

Do we need 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 supported.

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.