Toward an on demand service-oriented architecture

IBM Systems Journal,  March, 2005  by C.H. Crawford,  G.P. Bate,  L. Cherbakov,  K. Holley,  C. Tsocanos

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* Continuous business process improvement--SOA allows a clear representation of process flows identified by the order of the services used in a particular business process. This provides business users with an ideal environment to monitor business operations. Process modeling is reflected in the business service. Process manipulation is achieved by reorganizing the pieces in a pattern (the components that constitute a business service). This allows users to change process flows while monitoring the resulting effects, thus facilitating continuous improvement.

* Customer-centric architecture--Existing architecture models and practices tend to be application-centric. As organizations evolve from an application orientation toward a service orientation, consumers or customers of the applications benefit. A customer-centric architecture provides a user-configurable approach versus a one-size-fits-all or prepackaged workflow. This enhanced flexibility is brought about by identifying and exposing services, as opposed to locking users into hardwired application flows.

On demand SOA requirements

Maximum benefit from an SOA implementation in an on demand environment occurs when the underlying enterprise computing infrastructure is virtualized and enabled for policy-based system management and when the IT policies have been derived in turn from the corresponding business policies.

The current focus in SOA is on process definition and application enablement by means of Web services or grid technologies and standards. The link between business process policy and IT policy through application enablement has yet to be defined. For instance, in the POR example described previously, the login service could be reused across many business processes. However, different processes have different policies concerning the user class of service, that is, the type of authorization required. The virtualized IT infrastructure must be capable of ensuring different types of security, based on business policy, within the specific technology used to enable the application (for example, Web services).

Any solution development for on demand SOA must focus on an integrated approach among the following: the on demand business-process transformation that is driving application enablement, the corresponding IT policy and governance, and the system management of virtualized resources based on service level agreements (SEAs).

The starting point for on demand SOA is business process transformation. At the core of business process transformation is the policy and governance regarding how different parts of the process are integrated. This business process policy is used to derive IT policies, QoS, and SLAs. All of these terms are related to the business process, but each has a different meaning, as described below:

* Policy--A policy is a high level statement of how things are managed or organized, including management goals, objectives, beliefs, and responsibilities. Policies are normally defined at air overall strategy level and can be related to a specific area, for example, security and management policies. Ill many instances, policies reflect the law or other mandated requirements to which the policies must adhere. This is especially true ill the case of security and privacy policies.