SOA, Service Definitions, Gaps & Standards Roadmap Harmonization

1. SOA, Service Definitions, Gaps & Standards Roadmap Harmonization (Joint effort between OMG, The Open Group, OASIS and W3C) By: OMG: James Odell, Harsh Sharma The Open Group: Ed Harrington, Chris Harding OASIS: Frank McCabe (absent), Joseph Chiusano W3C: TBD..

2. Table of Contents • Harmonization Objectives • Existing definitions from standards groups for “SOA” and “Service” • A harmonized Definition of SOA • A harmonized Definition of Service

3. Harmonization Objectives • To agree upon and publish a common definition of SOA and Service across the major standards bodies • Identify which gaps and standards are being addressed by whom • Publish a joint SOA Standards Roadmap to the industry

4. Some Existing Definitions - Service-Oriented Architecture • The Open Group: An architectural style that supports a way of operating a business enabled by services and the outcomes that they bring {ensure relationship between linked services} (Note: This definition is currently in progress for the Open Group, see updated definition on slides 5,6) • Oasis: Service Oriented Architecture (SOA) is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. In general, entities (people and organizations) create capabilities to solve or support a solution for the problems they face in the course of their business. It is natural to think of one person’s needs being met by capabilities offered by someone else; or, in the world of distributed computing, one computer agent’s requirements being met by a computer agent belonging to a different owner.There is not necessarily a one-to-one correlation between needs and capabilities; the granularity of needs and capabilities vary from fundamental to complex, and any given need may require the combining of numerous capabilities while any single capability may address more than one need. The perceived value of SOA is that it provides a powerful framework for matching needs and capabilities and for combining capabilities to address those needs. • ZapThink: "Service-oriented architecture is an architectural discipline that centers on the notion that IT assets are described and exposed as Services. These Services can then be composed in a loosely-coupled fashion into higher-level business processes, which providing business agility in the face of IT heterogeneity."

5. The Open Group Definition: Service Oriented Architecture An architectural style that supports service orientation • Service orientationA way of a way of thinking in terms of services and service based development and the outcomes that services bring • ServiceA logical representation of a repeatable business activity that has a specified outcome (e.g., check customer credit; provide weather data, consolidate drilling reports), is self-contained and maybe composed of other Services. It is a black box to consumers of the Service • Architectural StyleThe combination of distinctive features in which Enterprise Architecture is done, or expressed • The SOA Architectural style’s distinctive features: • Based on the design of the services comprising an enterprise’s (or inter-enterprise) business processes. Services mirror real-world business activity • Service representation utilizes business descriptions. Service representation requires providing its context (including business process, goal, rule, policy, service interface and service component) and service orchestration to implement service • Has unique requirements on infrastructure. Implementations are recommended to use open standards, realize interoperability and location transparency. • Implementations are environment specific, they are constrained or enabled by context and must be described within their context. • Requires strong governance of service representation and implementation • Requires a “Litmus Test", which determined a “good services”

6. The Open Group: Service Oriented Architecture: A layered approach to architecture

7. Some Existing Definitions - Service-Oriented Architecture • W3C: A Service Oriented Architecture (SOA) is a form of distributed systems architecture that is typically characterized by the following properties: • Logical view: The service is an abstracted, logical view of actual programs, databases, business processes, etc., defined in terms of what it does, typically carrying out a business-level operation. • Message orientation: The service is formally defined in terms of the messages exchanged between provider agents and requester agents, and not the properties of the agents themselves. The internal structure of an agent, including features such as its implementation language, process structure and even database structure, are deliberately abstracted away in the SOA: using the SOA discipline one does not and should not need to know how an agent implementing a service is constructed. A key benefit of this concerns so-called legacy systems. By avoiding any knowledge of the internal structure of an agent, one can incorporate any software component or application that can be "wrapped" in message handling code that allows it to adhere to the formal service definition. • Description orientation: A service is described by machine-processable meta data. The description supports the public nature of the SOA: only those details that are exposed to the public and important for the use of the service should be included in the description. The semantics of a service should be documented, either directly or indirectly, by its description. • Granularity: Services tend to use a small number of operations with relatively large and complex messages. • Network orientation: Services tend to be oriented toward use over a network, though this is not an absolute requirement. • Platform neutral: Messages are sent in a platform-neutral, standardized format delivered through the interfaces. XML is the most obvious format that meets this constraint.

8. Some Existing Definitions – Service • The Open Group: A repeatable business {activity} that has a specified outcome. (e.g., check customer credit; open new account) {activity} – need to ensure word enables service to be a ‘black box’ that delivers a goal without specifying how it is implemented; Service is a black box. • W3C: A service is an abstract resource that represents a capability of performing tasks that represents a coherent functionality from the point of view of provider entities and requester entities. To be used, a service must be realized by a concrete provider agent. Where: A resource is defined to be anything that can have an identifier. In particular, it incorporates the concepts of ownership and control: a resource that appears in this architecture is a thing that has a name, may have reasonable representations and which can be said to be owned. The ownership of a resource is critically connected with the right to set policy on the resource. A capability is a named piece of functionality (or feature) that is declared as supported or requested by an agent. A provider entity is any entity that offers a service. A requester entity is any entity that wishes to use a provider entity’s service. A provider agent is an agent that is capable of and empowered to perform the actions associated with a service on behalf of its owner — the provider entity.

9. Some Existing Definitions – Service • Oasis:The means by which the needs of a consumer are brought together with the capabilities of a provider.Where: A capability is a real-world effect that a service provider is able to provide to a service consumer.A service is a mechanism to enable access to a set of one or more capabilities, where the access is provided using a prescribed interface and is exercised consistent with constraints and policies as specified by the service description. A service is provided by one entity – the service provider – for use by others, but the eventual consumers of the service may not be known to the service provider and may demonstrate uses of the service beyond the scope originally conceived by the provider. A service is accessed by means of a service interface, where the interface comprises the specifics of how to access the underlying capabilities. There are no constraints on what constitutes the underlying capability or how access is implemented by the service provider. Thus, the service could carry out its described functionality through one or more automated and/or manual processes that themselves could invoke other available services. A service is opaque in that its implementation is typically hidden from the service consumer except for (1) the information and behavior models exposed through the service interface and (2) the information required by service consumers to determine whether a given service is appropriate for their needs.

10. Keywords from Existing Definitions of SOA & Services Many of the available SOA & Service definitions have at least the following keywords: • abstracts complexity • business process execution • business-oriented architecture • standardizing interfaces • self-contained services • autonomous services • loosely-coupled • standard protocols • independent but collaborative • dynamic integration • reusable services • service composition • Policy • Contract • Directory of Services

11. OMG Working Definition - Service-Oriented Architecture • Possible OMG Definition*: Service Oriented Architecture (SOA) - an architecture for developing, deploying and managing semantically enriched, loosely coupled, platform-independentwork units composed as ‘Services’ among Providers and Consumers to support business functions. • Not all uses of web services are SOA *The above definition was deemed too technical by the participants

12. OMG Working Definition - Service-Oriented Architecture • Definition discussed and distributed to soa@omg.org on 4/25: Service Oriented Architecture is an architectural style for a community of providers and consumers of services to achieve mutual value, that: • Allows participants in the communities to work together with minimal co-dependence or technology dependence • Specifies the contracts to which organizations, people and technologies must adhere in order to participate in the community • Provides for business value and business processes to be realized by the community • Allows for a variety of technology to be used to facilitate interactions within the community

13. OMG Working Definition - Service • Possible OMG definition • A Service is a ‘unit of work’ performed by a ‘Service Provider’ to achieve desired capability for a ‘Service Requestor’ under a ‘Contract’ optionally facilitated by a ‘Service Broker’ • Services could be aggregated to perform an end-to-end Business function or a stand-alone fine grained function • A Web Service is a ‘Type of Service’ (not all Services are Web Services) • Services can be aggregated to a Composite Service