The reality of SOA – based on Web Services

Jochen Schroll recently brought my attention to two very interesting articles from IEEE and HICSS about the performance of web services in a Service-Oriented Architecture (SOA). Today, we are all taking about the value of thinking service oriented. SOA is much than a traditional information systems development because it embraces business process modelling and enterprise architecture as well as object-oriented design and distributed systems. But, I believe that it is critical that we also pay attention to some of the technical challenges that comes with the value of using SOA as our pattern for designing distributed systems.
From a strategic business perspective, SOA is built around the notion that services map to business functions. Within computing, the term architecture can refer to lower levels of abstraction, such as a particular computer’s or family of computers’ internal architecture. But SOA generally refers to organizational IS architecture, meaning the unifying or coherent form being used to organize and design the construction, selection and interconnection of an organization’s hardware, software and communications assets. In this way, SOA is an architectural style for building loosely coupled distributed systems that deliver application functionality as services to be used for end-user applications.
Technically the ideas behind SOA build on SOC, a computing paradigm in which services are the fundamental elements for developing applications. In this paradigm ICT products are comprised of references to external components for the performance of various kinds of service. SOC can be used to wrap a service-oriented facade around closed-architecture legacy systems, thereby converting these to be compatible with more open architectures. A SOA framework can take advantage of these wrappers to enable more flexible and cost-effective integration of financial services that continue to use legacy systems, especially in distributed settings.
In many SOA implementations the promotion of well defined, published, and discoverable interfaces is based on web service technology. But what do we know about the performance when we use web services to integrate our IT-infrastructure? Well, according to the IEEE article XML parser, transport protocol, and the overhead of the new proxies in web services affect both the scalability and the latency of the reengineered application. As you might know from reading my blog, I am not a deep technical person. But, having read the two articles (and talked to colleagues about them) I strongly believe that we must consider these technical challenges very carefully before we engage in full blown SOA projects at the national, regional as well as local levels of government. Hopefully, my experiences here in DC with IBM and the federal agencies will shed some practical light on that…