Saturday, February 26, 2005

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. more
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.

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