SOA - The basics

SOA is not latest trend anymore. Companies all over the world has committed a significant IT budget for this.

SOA is basically a collection of services which communicate (via messaging) with each other. Fundamental principle behind SOA is Strong cohesion and Loose coupling. Coupling is about interdependence of one subsystem with other subsystems. Cohesion of a subsystem characterizes its internal interdependencies.

SOA is not only about web-services. A good SOA may be started by provisioning few services from existing mission critical legacy applications. Better to start small and think big.

Numerous books exist on SOA. Messaging solutions are critical to any SOA. I prefer starting with Enterprise Integration Patterns. A good place is www.enterpriseintegrationpatterns.com which discusses 65 patterns suggested by Hohpe and Woolf.

Some good place to visit for SOA -

http://www.service-architecture.com/web-services/articles/service-oriented_architecture_soa_definition.html

http://en.wikipedia.org/wiki/Service-oriented_architecture