April, 2008
by Jaqui Lynch
For over 28 years, Jaqui has been responsible for projects across multiple platforms, including mainframes and UNIX/LINUX systems. From 1991 till May 1999, Jaqui worked at Boston College as the Manager of Systems Services. Jaqui spent 4 years freelance consulting on UNIX and Performance and Capacity Planning and now works for Mainline Information Systems as a Senior Systems Engineer focusing on pSeries and Linux. Jaqui has been involved in CMG since 1988 when she was a founding member of the New Zealand CMG group. She was the President of CMG in 2004 and 2005.
About the Author
Jaqui Lynch, Senior Systems Engineer, Mainline Information Systems
Over the past 30 years I've seen many technologies come and go in and out of fashion and can't even keep track of the number of acronyms. Every time a new acronym comes out someone hypes it as a paradigm shift and so it begins. So, is service-oriented architecture (SOA) yet another short-lived hot-button acronym found in an airline magazine or does it truly offer value in the IT enterprise? I think SOA is useful and here to stay, and hopefully you'll agree after reading this article.
SOA is a framework or architecture that allows IT assets to be organized into discrete components (called services) that can then be made available to applications to use. At the basic level, SOA is a collection of services that communicate with each other. This can be as basic as two services passing data, or it can be more complex and involve more coordination.
A service is any repeatable business task. In IT terms, this means a well-defined, self-contained function or entity that's independent. The features that allow the integration and linkage of these services are enabled by middleware software that's commonly referred to as an enterprise service bus (ESB). The ESB isn't necessarily Web services-based, but it's standards-based and needs to support many middleware or transports. The ESB's purpose is to provide the necessary messaging technologies and routing such that disparate systems or applications can talk to each other.
Where SOA differs from previous technologies is that it's more of an architecture that enables the integration and reuse of services through applications based on many technologies, including Web services. The key requirement is the services must be independent, and that they're written to predefined standard interfaces that make it easy for the services to communicate with each other. The services should also communicate in a manner that's independent from the underlying hardware, software or programming language. The interface definition hides most of this platform and language specific information such that an application should be able to call the service using the interface with no regard to whether the service is Java, .NET, C++ or another language, and with no regard to what hardware or operating system the service is running on. This interface definition is critical to the ability to provide reuse of services.
The intent of SOA is to provide a framework that combines tools and technologies in such a way that it's possible to implement new services and applications. This allows IT to be more responsive to changing business needs while retaining control over costs. SOA is showing great promise in this area.
Several characteristics are common to the general IT approach to solving business problems, including having a focus on technology or function, being reactive, working in silos in a very ad-hoc manner and being heavily IT-focused. IT constantly struggles with how to adapt quickly to changing business needs while still maintaining system stability and security. Over the years, many new regulations have been introduced (e.g. HIPAA and Sarbanes-Oxley Act) that have exacerbated this problem even further. IT now has to deal with Web-based systems that go across international borders and that run 24-7. Companies deal with a world where competition is fast and furious and they must be able to develop a new application quickly in order to stay competitive. Clearly the current IT focus on technology and functions isn't conducive to rapid, reliable change.
SOA, on the other hand, is more focused on the business and the coordination of resources. It's built to be flexible, designed to be integrated and its services are repeatable. The orientation is service-based, not operations-based, making it a prime contender in the architecture battle to renovate IT focus. This shift in focus to a more service-oriented approach allows SOA to provide a more flexible environment because everything is coded to APIs or well-known interfaces. This provides maximum code reuse and a simpler integrated environment.
SOA Enterprise Service Bus
Probably the easiest way to understand the concepts of SOA is to think of it in terms of enabling On Demand services. The key component in this is the Enterprise Service Bus, which provides the transparent interconnection of services. Figure 1 below shows a diagram of how this looks.
Figure 1 Enterprise Service Bus - Source IBM
As with all frameworks and architectures, a cultural change is necessary in order to have a successful migration into the new environment. The key to success here is that all of the processes and services that enable SOA need to be well documented to provide the reuse necessary to truly take advantage of SOA. Management buy-in is also necessary at the highest levels to map this out, rather than just waking up one day and saying, "today we will start implementing SOA."
SOA can reenergize a business and an IT department if proper planning is put in place ahead of time, if both the business and IT understand that this is a priority within the company, and if it's supported from the highest levels down. Education is another key component of reorganizing into an SOA world. As we all know, technology is rarely the reason that new technologies or architectures fail--in general it's due to a lack of organizational commitment, unreasonable timeframes or expectations. SOA is no panacea--it's another architecture where proper planning and education can make a huge difference to the business' success.
While SOA shows great potential in helping speed up application development and integration and provides a great foundation for collaboration, it's important to remember that SOA is only part of the answer and needs to be viewed as part of an overall framework for the business. SOA isn't going away any time soon and should be reviewed for its potential as one of the tools in the IT and business toolkits.