A2A


		Application 2 Application Services Application 2 Application Services is services which orchestrates services from several applications, typically asynchronous and workflow-backed. I.e. a Auction type request against a set of suppliers or an booking/order/delivery process.			Suggestion for a more presise definition An A2A service is a service which is responsible for collaboration between several human or automated actors.


Characteristics Two types: Process Services - Services orchestrated to produce real business value - Workflow-oriented processes - Orchestrated functionality from several services - ACS/CS services as Business/Domain Objects - External applications for sub-processes & tasks - Long running processes - Should not have any long-running transactions - Could (should) have cache (state full) Application Integration Service Endpoints - Services which integrate and map against external application endpoints - Should (internally) provide for SLA and contractual requirements (via cache, rebind, fail-over and such) - Works as an external data anti-corruption layer for external application endpoints to reduce dependencies and facilitate evolve ability Patterns for Application 2 Application Services ---		Application 2 Application Services


P1. A service shall have one named owner	P2. A service shall provide documented business value	P20. All services shall be in the service universe	P21. A service shall be categorized (OW SOA category)	P22. A service shall have an "authentication, authorisation, endpoint strategy"
P23. A service shall document its Service Level Agreement SLA (response time, availabillity++)	P3. A service shall do one only thing, and one thing well	P30. A service shall have a versioning strategy (ACS, CS)	P31. A service shall provide for audit and monitoring of service usage	P31. A service shall provide for audit and monitoring of service usage
P41. A service shall provide heartbeat and traffic monitoring	P90. A service shall have a documented coupling to the contractual and requirement for service usage