- A service is an indivisible unit of work
- A service is independent of the protocol or implementation
- There will be one and only one service producer
- There can be multiple instances of the same service
- An entity that utilized the service is called the service consumer
- There can be one or more service consumers for a given service
- A line between the services is the agreement between the producer and the consumer
- A service can invoke other services, thereby, creating a hierarchy of services
- A service not consumed by any producer is an orphan service
- SOA Theorem #1 SOA Governance observers Newton's laws of motion
- SOA Theorem #2 IT Funding observers Archimedes' principles
- SOA Theorem #3 The need to Enterprise Service Bus shall diminish over time
- SOA Theorem #4 Service hierarchy should not exceed more than three levels
- SOA Corollary #1 Dynamic Service Discovery does not require centralized repository (Corollary to SOA Theorem #3)
- SOA Corollary #2 All service containers need to count and limit service hops (Coroloary to SOA Theorem #4)
For those not familiar with these tersm following are the Wikipedia defintions
Postulates: The term postulate, or axiom, indicates a starting assumption from which other statements are logically derived. It does not have to be self-evident (constancy of the speed of light in a vacuum is not self-evident, however it was used as a postulate in the special theory of relativity). Some axioms are experimental facts, but some are just assumptions not based on anything.
Theorems: In mathematics, a theorem is a statement, often stated in natural language, that can be proved on the basis of explicitly stated or previously agreed assumptions. In logic, a theorem is a statement in a formal language that can be derived by applying rules and axioms from a deductive system. This definition in logic is crucial in fields such as proof theory that study the general properties of provable and unprovable statements.
Corollary: A corollary is a mathematical statement which follows easily from a previously proven statement, typically a mathematical theorem. The use of the name corollary in place of proposition or theorem is usually subjective: proposition A is a corollary of proposition B if A can be deduced quickly and easily from B, but the meaning of "quickly and easily" varies depending upon the author and context. Sometimes a corollary has a proof which explains the derivation; sometimes the derivation is considered to be self-evident.