Often when I start discussing SOA, a story comes to my mind that I first heard from my grand father when I was kid. It is about six blind men who encounter an elephant for the first time in their life. They perceive the animal differently and start fighting amongst themselves. One who touched its tail thought it was a snake, another who got hold of his trunk thought it to be a tree branch, the third, bumping against his rigid body, thought it was a wall while the fourth, getting hold of his legs, thought it to be a log of wood and so on. Later on they were made aware by a wise man that each of them was correct in their own perspective and that the elephant is all of what they sensed and much more.
In today’s SOA context, I see the perfect applicability of the elephant’s story. Is SOA just implementing SOAP/HTTP or do we need all web services standards for rightly implementing SOA? Is wrapping legacy applications with well-defined service interface all we need for SOA or do we need a top-down approach of Business Process Management to successfully implement SOA? Do we need a full-blown ESB or is it fine to use point-to-point invocation? This article highlights that SOA is multi-dimensional and that the answer to all the above questions depends upon an organization’s current SOA maturity and its requirements. Organizations shall be able to reap the SOA benefits at its fullest level only when it recognizes the multi-dimensional aspect of SOA and takes action to progress at each of the dimensions of SOA.
At the highest level of abstraction in a corporation, there exists a Business and an IT view of SOA. Business is concerned about the business goals, business performance, and business strategies. Dealing with the above business concerns, the business perspective of SOA relates to business process flow and the resultant business events, the business activity monitoring and its optimization. The business dimension of SOA is an important aspect of SOA that we tend to ignore by hiding SOA in the IT realm. The other SOA perspective at the same level in the organization is the IT perspective. This aspect of SOA deals with design and implementation of business services. It is about the various architecture aspects of SOA, on the semantic model, about services routing and orchestration. It is about services implementation and execution.
Moving down a level of abstraction, SOA can be viewed from a management dimension and from the architecture dimension. The management dimension of SOA deals with planning, execution and optimization of SOA program. This dimension deals with governance, monitoring and methodology along with areas such as change management and execution support. Next comes the A in SOA that is its architecture dimension. The Architecture of SOA draws upon the dimensions from the Enterprise Architecture. These are the Services Oriented Business Architecture (SOBA), Services Oriented Information Architecture (SOIA) , Services Oriented Application Architecture (SOAA) and Services Oriented Technical Architecture (SOTA). The business services being the digital model of the business process, the business architecture dimension of SOA is related to defining, modeling and executing the business processes and its subsequent monitoring and optimization. The next “A” is the Information Architecture that is the life-blood of SOA. It is the information that is exchanged between the services provider and consumer. SOIA deals with the semantic modeling of information and with meta-data management. The SOAA deals with the services design, implementation, and services interaction with the SOA platform. It also deals with customer access and enterprise data access and business process orchestration. Additionally, it takes into account the various levels of integration. At the highest level is the business process integration and closer to data is the data level integration. The SOTA deals with design, implementation and execution platform.
It deals with the infrastructure and its related service levels.
At the lowest level of abstraction we have the producer and consumer perspectives of SOA. While the producer deals with SOA implementation, the consumer deals with SOA usage. These dimensions are such that taking a vertical slice across these abstractions provides a unique view of SOA. For a provider and consumer alike there is an architecture dimension for Business and IT of SOA. Similarly, for a provider and consumer alike there is a management dimension for Business and IT of SOA.
This article emphasized that organizations whom acknowledge SOA is multi-dimensional, shall be able to scale SOA program to an enterprise level and consequently would be able to reap the maximum benefits. In the next series of articles I shall perform deeper dives into each of these SOA dimensions.
