OASIS Reference Model for SOA by iqm86975


									      OASIS Reference Model for SOA
1.   Introduction
2.   Terms
3.   Facts
                                - Introduction -

• The reference model for service oriented
  architectures, approved by OASIS in October
  2006, has been used as a guideline to identify
  and separate different categories and aspects
  around organizational interoperability.
                        - Terms -

•   Service
•   Visibility
•   Interaction
•   Contract
•   Policy
•   Information model
•   Behaviour model
                                                        - Facts (1/8) -

•   Service
     – The notion of a service stands in the focus of the reference model. A
       service is defined by the six concepts:
         • Visibility
         • Interaction
         • Service description
         • Contract and policy
         • Real world effect
         • Execution context

                                            Figure 1: Definition of a “Service”
                                                - Facts (2/8) -

• Visibility
   – is defined as the relationship between a service provider and a
     service user that is satisfied when they are able to interact with
     each other. Visibility as a concept is defined by three sub-
     concepts called awareness, willingness, and reachability.
     Service awareness requires that the description of a service
     including service policies and contracts is available and can be
     retrieved by potential service users. Willingness as a term
     defines the willingness of the partners to co-operate.
     Reachability defines if a customer is able to reach and use a
     service from a technical point of view.
                                  - Facts (3/8) -

Figure 2: Concept of Visibility
                                                 - Facts (4/8) -

•   Interaction
     – is the activity of using a service. Typically mediated by the
        exchange of messages, an interaction proceeds through a series
        of information exchanges and invoked actions. Interactions are
        defined by two concepts called information model and behavior
        model. The information model defines the structure/syntax of the
        information that may be exchanged with a service. The behavior
        model consists of the action model and the process model. The
        former defines the format of the exchanged requests and
        responses, the latter specifies the temporal relationships and
        properties of actions and events associated with the invocation
        of a service.
                                   - Facts (5/8) -

Figure 3: Concept of Interaction
                                                   - Facts (6/8) -

•   Policies and contracts
     – Policies represent constraints or conditions on the description
       and use of services, defined either by the service owner or by
       the service user. A contract represents an agreement between
       the participants about the conditions that have to be considered
       during the usage of a service. Specific forms of security, privacy,
       availability, performance and other service qualities are
       examples for policies. Additionally contracts can represent
       limitations on the usage of a service and commercial
       agreements. Thus contracts and policies are of special
       importance for organizational interoperability.
                                      - Facts (7/8) -

Figure 4: Concepts of Policies and Contracts
                                                        - Facts (8/8) -

•   Concepts for OI
     – Organizational interoperability can be discussed using the four concepts
       service visibility, behavior model, information model, contract and policy.

        Figure 5: Selected concepts for OI

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