SOAs and ESBs
The service-oriented architecture (SOA) initiative has emerged as an answer to bridging these business needs to existing IT implementations. Using an SOA model, application functionality is exposed in the form of services representing discrete business operations. These business services can themselves then become elements of other business services as more and more complex business processes are constructed. The aim is to implement a technical approach to delivering IT-based business functionality where IT resources can be regarded as a pool of building blocks that can be reused in the creation of new services needed to bring about business change. Once this is achieved, it becomes quicker, cheaper and easier to respond to new business trends, enabling companies to achieve a much higher degree of business agility.
So it is no great surprise that SOAs have become the topic of the moment. But many companies are now starting to struggle with the technical challenges of implementing this liberating form of IT deployment. Some technologies like web services have already been identified that can help with parts of the SOA implementation challenge, but there is still confusion over what it takes to build a successful SOA deployment. Also, a lot of implementation options considered today require a major up-front infrastructure investment, both in terms of cost and general disruption, before the benefits can start to flow. This introduces a significant amount of business risk, with little opportunity to validate the SOA benefits before extensive financial outlay is made.
However, one recent technological development offers relief from these issues. Over the past year or two the Enterprise Service Bus (ESB) market has emerged, and is rapidly becoming a key foundation for the SOA and wider integration strategy for many companies. ESB products address many of the functional prerequisites to establishing an SOA, and at the same time they support an incremental deployment model which enables deployment in a piecemeal fashion, where investment can be made on a gradual basis, balanced against a growing level of return. This combination in turn promises a safe and secure option for delivering an SOA while simultaneously controlling the level of business risk involved.
This paper considers the ESB and its applicability to developing an SOA infrastructure in more detail, concluding finally that the ESB is indeed an ideal enabler for developing and deploying service-oriented business applications (SOBAs) and exploiting the advantages of loosely coupled systems to achieve the level of business agility so desperately desired by executive management teams today.