Navigating the SOA Open Standards Landscape Around Architecture
Given how much SOA has invaded the industry mentality over the recent years, it is surprising how few standards there are relative to other technologies such as CORBA, Enterprise Java or Web Services. Of course there are the various WS-* standards and specifications that many people associate with SOA, but in terms of those that are deliberately implementation agnostic the OASIS Reference Model for SOA stood alone for quite a while. Earlier this year the OMG released the SOA Modeling Language and The Open Group announced the formation of a SOA Working Group as well as releasing a SOA Source Book.
Over the past few months members of all of these efforts and others have been working to try to reconcile these various efforts and have now released a new white paper called Navigating the SOA Open Standards Landscape Around Architecture (available on all of their web sites). As the paper states:
This joint white paper explains and positions standards for SOA reference models, ontologies, reference architectures, maturity models, modeling languages, and governance. It outlines where the works are similar, highlights the strengths of each body of work, and touches on how the work can be used together in complementary ways. It is also meant as a guide to users of these specifications for selecting the technical products most appropriate for their needs, consistent with where they are today and where they plan to head on their SOA journeys.
The specifications and efforts examined in the paper include the OASIS Reference Model for SOA, the OASIS Reference Architecture for SOA Foundation, the OMG SoaML Specification, The Open Group SOA Ontology, The Open Group SOA Reference Architecture, The Open Group SOA Governance Framework, and The Open Group Service Integration Maturity Model.
This is a good addition to the SOA library. The white paper is deliberately technology agnostic, staying clear of referencing implementation approaches to SOA such as Web Services or JBI. On the one hand that can be seen as a good thing keeping vendor hype out of the picture and potentially increasing the longevity of the paper. But on the other hand questions may be asked as to the practicality of what is reported.
According to a white paper, existing standards can be grouped in the following categories:
- Reference Models - an abstract framework for understanding significant relationships among the entities of some environments. White paper cites the OASIS Reference Model for SOA, which
capture the "essence" of SOA, as well as provide a vocabulary and common understanding of SOA. The goals of the reference model include a common conceptual framework that can be used consistently across and between different SOA implementations, common semantics that can be used unambiguously in modeling specific SOA solutions, unifying concepts to explain and underpin a generic design template supporting a specific SOA, and definitions that should apply to all SOA.
- Reference Architectures - can be defined at different levels of abstraction ranging from foundational architectures to common systems architectures, and industry and organization-specific architectures. Several technical products are available in this category. OASIS Reference Architecture for SOA Foundation provides
a view-based abstract reference architecture foundation that models SOA from an ecosystem/paradigm perspective. It specifies three viewpoints; specifically, the Service Ecosystem viewpoint, the Realizing SOAs viewpoint, and the Owning SOAs viewpoint.The Open Group SOA Reference Architecture provides:
the basis, or blueprint, for an enterprise architecture so that the enterprise architect can use that template or blueprint as a standard that will be instantiated during each individual project or solution that is being developed. This will be performed within the organization where the SOA reference architecture will be instantiated. This SOA reference architecture is designed to support different kinds of scenarios including those involving consumer organizations, vendors, other standard bodies, and other Open Group projects.
- Ontologies - explicit formal specification of the terms in the domain and relations among them. White paper cites the The Open Group SOA Ontology, which
captures a set of related concepts within the SOA space and explains what they are and how they relate to each other. The objectives are to facilitate understanding of these terms and concepts within the context of SOA, and potentially to facilitate model-driven implementation. The ontology is represented in OWL (Web Ontology Language) to enable automation and allow tools to process it.
- Maturity Models - representing means for both evaluating and assessing the current maturity state. They also provide means for developing a value proposition and transformation roadmap to achieve a target state of maturity from a given current maturity state. The paper cites The Open Group Service Integration Maturity Model (OSIMM) which
provides corporations and IT practitioners with a means to assess an organization’s maturity within a complete SOA migration path. It provides a process to create a roadmap for incremental adoption which maximizes business benefits at each stage along the way. The model consists of seven levels of maturity and seven dimensions of consideration within an organization or scope defined by a project, and acts as a quantitative model to aid in assessment of a current state and designation of a desired future state.
- Modeling Languages - defining a metamodel and notation for providing a standard way of representing artifacts in tools and in communicating information between tools and automated environments. A modeling language such as the Unified Modeling Language (UML) from the OMG may be extended by profiles that tailor a model or modeling language for a specific domain or purpose. The paper cites OMG’s SOAML, which
extends UML in order to provide additional capabilities for managing cohesion and coupling afforded by an SOA style. SoaML is applicable across a broad range of domains and levels of abstraction from business services to detailed IT services. Using a common language for these different purposes simplifies systems modeling and integration of separate concerns in order to enable business agility which can be represented with business architecture models such as BMM and BPMN. SoaML can be viewed as supporting instantiation of the OASIS Reference Model for SOA that provides a concrete platform for services modeling...
- Concrete/Solution Architectures - instantiations of a reference architecture achieved by substitution of the general, logical, abstract elements of the template with concrete or physical realizations by vendor products and instances of technical products, standards, protocols, and design/architectural decisions. The examples of the industry reference architectures provided by a white paper include ARTS XML SOA Blueprint for Retail and the Service Oriented Realization of the HTNG Reference Architecture.
As the white paper explains, although there is a wide range of SOA standards
...there is a great deal of agreement on the foundational core concepts across the many independent open specifications and standards for SOA.
These standards are related and are building on each other.
The white paper is a great document, simplifying navigation between different standards, their relationships and how and where to use each standard.