Are Enterprise Architecture and Service Oriented Architecture one and the same? Does the EA and SOA difference matter?
Quite often the alphabet soup of acronyms and buzzwords gets in the way of them being effectively implemented. For example, take Enterprise Architecture Planning, EA or EAP if I may, and Service Oriented Architecture aka SOA. The conversation around EA and SOA makes them look and feel alike. Are they?
The answer, as you may have guessed is an overwhelming no. Complementary? Yes. Same? No.
Let me explain.
The purpose behind having an enterprise architecture is to get a bird’s eye view of IT assets deployed in an organization. This bird’s eye view provides critical information to maximize IT ROI. For example, we can tell if there are overlaps i.e. two assets deployed for the same purpose. By consolidating these assets one can theoretically lower cost of operation thereby increasing IT ROI.
Enterprise Architecture is a 50,000 foot level activity. However, it has many layers which incrementally get more granular. At what point do we stop getting more specific? Well, till we get to the major IT components – hardware, software etc.
Service Oriented Architecture was supposed to provide a software design – not architecture – so that enterprise wide software development follows a consistent path. So standards driven reuse across the enterprise becomes a reality and waste – both in terms of time and money – is reduced and eventually eliminated.
In the hierarchy of things SOA is a layer below EA. In the continuum from business to technology SOA is a milestone below EA, just like EA is a milestone below IT Strategy and Systems Architecture is a milestone below SOA. EA is the architecture and SOA is the design.
One can think of SOA as converting EA into incrementally detailed or specific diagrams or schematics. Alternatively, SOA can be thought of as getting Enterprise Architecture implementation ready.
EA and SOA are not interchangeable. EA is a must but SOA can be replaced with the flavor of the month design methodology. Before Object Orientation i.e. SOA, the favorite used to be Structured Design (For example, Ed Yourdan’s methodology and the much hyped Information Engineering). EA has been EA for ever.
Yes, Zachman is being modified/replaced by Object Oriented EA. Yes, the 3 layer EA is being replaced by the 5 layer EA. However, these are at best modifications to the concept not a fundamental rethink of it.
So why is there such confusion between EA and SOA?
For starters, they are adjacent layers so they can “bleed” into each other. Then there is the issue of objectives being confused for the means. EA and SOA both have the same objectives – improve IT ROI through eliminating overlap, filling gaps, promoting reuse etc.
Enterprise Architecture and Service Oriented Architecture are both trying to get to the same objectives but they are complementary steps in the same process not overlapping or mutually exclusive or redundant steps in different processes.
