Differences EAI and SOA
Enterprise Application Integration (EAI) refers to techniques used to share data and processes within an organization, and Service Oriented Architecture (SOA) is one of those techniques. The term EAI has evolved from being merely describing techniques use to share data, to include techniques use to share both data and processes.
Before the rise of SOA, we were mainly concern with making software applications work together and share data. This was relatively easily accomplished by RPC point to point style of EAI. As the business and IT evolved, the number of applications needed to be integrated gradually increased. The P2P style of EAI resulted to an inevitably complex mesh network system. The next step in the evolution of EAI was targeted toward reducing the complexity of the integrated systems. This was the birth of the middleware systems. EAI moved to the hub and spokes style of integration. This was implemented using integration platforms like CORBA and DCOM. The hub and spokes style of EAI was successful reducing complexity but we soon discovered that the resulted systems were tightly coupled and rigid by the nature of their design and could not response to changes in business requirements. ( There was a famous saying that do not change a working application module because it would break the entire sytem).
If the hub and spokes style of EAI design did not sustain the business in the long run, it means something ( very crucial to the survival and growth of the business) must have been left out of the design equation. Yes, the key fact that a business is a collection of processes that may change with time was being taken for granted. SOA has come in to closed the gap that existed between the design of a system and the business that the system is designed to support. SOA is not only an Architectural Design Style and Principles but a strategic business oriented discipline that can help the an organization remain agile and grow. The inclusion of the fact that business process varies with time into the SOA style of EAI, enable SOA to have a key capability not exhibited by previous EAI styles of integration. SOA provides us with the capability to assemble existing services to orchestrate new business processes in a lousely coupled way.
As more and more organizations become aware of the business value of SOA, we are currently shifting from a vision of Enterprise Application Integration to one Enterprise Services Integration. Today, major ERP vendors are breaking down their giant ERP systems into service modules that you can buy and integrate as you need. For those of us doing SOA consulting, it is like finding the ultimate theory that unifies Business and IT.
To be continue…