SOA – Approach – Bottom vs Top

In a meeting earlier this month, I was presented the Top-Down approach to Service Oriented Architecture (SOA). Those of you who know me, know I love driving solutions from business need to process model to solution, so this resonated very nicely with me.

Top-Down is very process centric, taking advantage of various modeling tools (Casewise being one of favorites). Some of the Enterprise players like BEA and Websphere have modeling tools that even help write the code for you. But this means that you really see SOA as a framework representing business processes. These composite applications access software functionality decomposed of a set of services both coarse and fine grained that are accessed through a central application layer.

Is this the only view…

How about Bottom-Up, this is for the action oriented group of us that are driving towards leveraging SOA to simplify integration, and see this as a model that allows for reusable interface components that gain access to data or application functionality, which needs to be inherently reusable.

As time progresses and the various proponents of SOA have a chance to work with these two approaches, I think you will find that both are correct in the right arena and assuming that you have a handle on registry and security. If these two items are fine, then what is wrong with either approach? The second will be faster and is more suited to the cost beaten IT Agile Innovator while the other is perfect for well structured business value driven solutions.

  1. mip Reply

    I hear you on the “let’s just get it done” aspect but I am always puzzled by initiatives that want to just jump in and get going. There never seems to be enough time to do it right, but there is always time to do it again!?!? I’m of the mindset that you approach it from the top, scope out what you are trying to achieve, create the process flows and go from there.

  2. Stephen Reply

    It is hard though as we all are more and more pressed to just get it done. I think with the emergence of SOA, we are going to see some proper thinking on approach as I think we all want to see value for our effort.

  3. mip Reply

    Excellent post Stephen. Really like the consideration given to both top-down vs. down-top. I personally am like you – I like the top-down approach where you start with processes.

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