IBM Websphere ESB Service Oriented Architecture

SOA is an approach to defining integration architectures based on the concept of a service. Applications collaborate by invoking each other services and services can be tranquil into larger sequences to implement business processes.

Drivers for SOA

The main driver for SOA is to define an architectural approach that aid in the flexible integration of IT systems. Organizations spend a considerable amount of time and money trying to realize rapid, flexible integration of IT systems across all elements of the business cycle.

The drivers behind this objective include: 

Increasing the speed at which businesses can implement new products and processes, can change obtainable ones, or can recombine them in new ways

Reducing implementation and ownership costs of IT systems and the integration between them enabling flexible pricing models by outsourcing more fine-grained elements of the business than were formerly possible or by moving from fixed to variable pricing, based on transaction volumes.

• Simplifying the integration work that is required by mergers and acquisitions
• Achieving better IT utilization and return on investment
• Achieving implementation of business processes at a level that is independent from the applications and platforms that are used to support the processes
• SOA prescribes a set of design principles and an architectural approach to achieve this rapid flexible integration. In the following sections we provide an overview of some of the elements in SOA that achieve this aim.

Definition of SOA:

SOA is an integration architecture approach based on the concept of a service. The business and infrastructure functions that are required to build distributed systems are provided as services that collectively, or individually, deliver application functionality to either end-user applications or other services.

SOA specifies that within any given architecture, there should be a consistent mechanism for services to communicate. That mechanism should be attached loosely and should support the use of explicit interfaces.

SOA brings the benefits of loose coupling and encapsulation to integration at an enterprise level. It apply successful concepts proved by Object Oriented development, Component Based Design, and Enterprise Application Integration technology to an architectural approach for IT system integration.

Services are the building blocks to SOA, providing function out of which distributed systems can be built. Services can be invoked independently by either external or internal service consumers to route simple functions, or can be chained together to form more complex functionality and so to quickly devise new functionality.

By adopting an SOA approach and implementing it using sustaining technologies, companies can build flexible systems that implement altering business processes quickly, and make extensive use of reusable components