Positioning
Since the OASIS SOA RA, The Open Group ontology, and the OMG SoaML were all based on the OASIS SOA reference model with refinements and extensions, there is some natural affinity between these works. Having a common “root” certainly helps increase the chances that the standards are consistent. It should be noted that the Open Group SOA RA is not based on or influenced by the OASIS SOA RM. However, from the start of the cross-consortium collaboration on the paper, there has been a bi-directional influence on the content of the SOA RA and governance specifications between OASIS and The Open Group.
The Navigating SOA paper positions the reference architectures along two continuums: level of abstraction (discussed in the Types of Architectures section) and coverage of enterprise architecture. The coverage continuum ranges from narrow, i.e. a particular pattern; to partial, covering on aspect, like governance; to end-to-end, which provides a comprehensive technical RA for IT; to complete, which covers IT and business.
We can position the SOA standards relative to each other along these two continuums in the following diagram:
Technically, the SOA RM and SOA ontology are not RAs, but it is useful to show them as the most abstract works surveyed. The OASIS RM is the most abstract, with The Open Group SOA ontology being slightly less abstract, since it provides a normative expression of the SOA RM with extensions.
The OASIS SOA RA is a conceptual architecture, but it is less abstract than the OASIS SOA RM and ontology since it provides significantly more detail on architectural components and their relationships, and provides less coverage since it details a subset of all of the architectural views available. Although The Open Group SOA RA is a generic architecture that is less abstract than the OASIS SOA RA, it provides architectural building blocks that are valid across industries and offers more coverage of architectural views, since it addresses IT and business concerns for SOA in an enterprise architecture.
The Open Group’s SOA governance framework is a generic, domain specific, partial reference architecture and can be categorized as a generic, partial RA. The OASIS SOA RA also includes SOA governance with a similar positioning. The other standards positioned in this section of the paper are just examples to further illustrate the continuum.
Conclusion
The “Navigating SOA” joint whitepaper accomplished its objectives by providing clarity and reassurance on the very confusing SOA standards landscape. The key concepts for SOA and SOA governance, as agreed on by these standards organizations, can be very helpful in understanding SOA fundamentals. Although they were a bit challenging to agree on, providing an explanation of the types of architecture standards and how they relate to each other is valuable in itself. In addition, the brief summary of the intent of each standard and its position relative to the other standards, acts as a mini “Cliff’s Notes” for these SOA standards.
One of the key, long-range benefits of the collaboration between OMG, OASIS and The Open Group, aside from the recently published paper, is the relationships between the organizations, their work groups, and authors. As these standards evolve, and new standards emerge, these relationships should help keep these SOA architectural standards as consistent as possible and reduce the need for a sequel.
However, there’s no magic here. While these standards are not inherently conflicting and can be used in complimentary ways, you still need to understand them, understand your business, and choose the right ones for your organization. The Navigating SOA whitepaper just makes that a little easier.
Heather Kreger is IBM’s lead architect for SOA Standards in Software Group with 15 years of standards experience. She has led the development of standards for Web services, management and Java in W3C, OASIS, DMTF, and The Open Group. Heather is the author of numerous articles and specifications, the book “Java and JMX, Building Manageable Systems”, and most recently, editor of “Navigating the SOA Open Standards Landscape around Architecture”.