SOA Principles

Several pundits have attempted to define the principles of Service-Oriented Architecture (SOA). Here is a summary of the SOA principles I have been propounding.

Service Ecosystem	Business viability depends on delivering services into a broader service ecosystem. Thus the service economy drives the business (which drives further services, which ultimately drive technology.)
Service Economy	Each service represents a unit of value. Services are regarded as intrinsically tradeable, and have both an exchange value and a use value. (Of course we may often choose not to exercise the option to trade services, for various reasons.)
Service Integrity	Each service represents a meaningful 'whole' from the user-side as well as from the supply-side. Service coherence, reliability and 'wholeness' promotes broad and robust use/reuse.
Loose Coupling / Rich Coupling	Open (typically asynchronous) connections between organizations, components and services. Interoperability between human activity and software services.
Differentiated Service	Functionality, quality or cost vary with circumstances, including identity and context. This helps to generate requisite variety in the service ecosystem.
Multiple Provision	Availability of alternative services or service implementations, biodiversity. This produces agile and robust systems, and also helps to generate requisite variety in the service ecosystem.
Complexity / Stratification	Complex networks of services must be understood as systems of systems. Such systems are generally organized in layers: one layer acts as a platform of services for the layer above.
Distributed Intelligence	Not only is functionality distributed across a network of services, but the intelligence governing this functionality is also distributed. Systems with distributed intelligence may be amenable to much more radical change than centralized ones.
Model-Based Management	Using business models to drive all aspects of system/service management seamlessly through development, testing/simulation and operations to provide a common understanding and visibility of systems and services to monitor and control all aspects of system design and operational performance.
Component-Based Business	Loosely coupled networks of independent business components.
Emergent Order	The service economy evolves into a continous network of value-adding services, through a series of structure-preserving transformations.

I shall try to expand and illustrate these in future posts.