Loosely Coupled Frameworks enable tightly aligned business integration  

While the title sounds like an oxymoron it is an important reason to develop a loosely coupled framework. There is a lot of discussion about the need for loosely coupled architectures but not much available on what they are and how they should be built. Doug Kaye presents a good one-liner and more to the point, a dicussion framework for loosely coupled versus tightly coupled.

Presenting similar concepts from a different viewpoint, I would propose the following definition:

This definition makes a major assumption - loosely coupled frameworks are part of a distributed system. There are three parts to this distributed system, 1) Service orientated architecture: the course grained business services (simple rule of thumb, if the business consumer does not understand the interface it is not a service 2) Web Services: this is the interface to the services, the universal jack to connect to 3) Loosely coupled framework: this is the glue that makes the evolution of business interactions possible.The objective is to design systems that enforce the protection of other parts of the system from change. This is enables organizations to use a loosely coupled framework to tightly align business objectives.

The perspective for this definition is, what is the intent of the loosely coupled framework? . Rather than how is it built or designed. More of the why rather than the how. They are both important but sometimes starting with why helps focus the discussion more tightly.

The first intent is decoupling individual services from each other in such a way that they can evolve independently. The second intent is to design systems with the assumption that services are going to have windows of availablitiy, i.e. things break. The third and final intent is that change is going to happen and needs to be designed for.

If several organizations are trying to align their business objectives the tighter the architectural integration the more brittle the business alignment becomes and any change becomes a n(n-1) problem where n is the number of other services connected. The objective of a loosely coupled architecture is to break this model and reduce the dependances to a minimum, while maintaining business process alignment.

The objective should be to increase the value of the system as more participants are added rather than the opposite. Good examples of this architecture today are Federal Express, Visa and the phone system. Each user of the system has a single interface to the system, as the number of participants increases, the value of the system increases, but the complexity for each user stays constant. This is the value proposition Grand Central and other web services networks. Grand Central is an implementation of a loosely coupled framework where the complexity for each service is defined by a single connection and where the value of this connection increases with the number of partners connected but not the complexity

The more loosely coupled you are the easier it is to tightly align your business processes and keep them aligned.

posted by John McDowall | 5:30 PM