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  1. 1. OASIS Service Oriented Architecture Reference Model Technical Committee (SOA-RM) BOOT CAMP April 13 2005 DRAFT: Not approved by the OASIS SOA RM TC.
  2. 2. Purpose <ul><li>This slide deck is designed to bring new TC members up to speed. </li></ul><ul><li>Work described herein defines what we have consensus on at present time. </li></ul><ul><li>CAVEAT: Subject to change in future </li></ul>
  3. 3. Agenda <ul><li>What is SOA; what is a reference model for SOA </li></ul><ul><li>Why is a reference model needed </li></ul><ul><li>The OASIS SOA RM TC </li></ul>
  4. 4. Defining SOA <ul><li>If Service Oriented Architecture is Architecture, as the name implies, it should be definable as architecture. </li></ul><ul><li>This should not be done by referencing specific implementations. </li></ul><ul><li>Definition of Architecture (from Charter): </li></ul><ul><ul><li>“ Architecture: A software architecture for a system is the structure or structures of the system, which consist of elements and their externally visible properties, and the relationships among them.” </li></ul></ul>
  5. 5. Closer look: “Service Oriented” <ul><li>Is a paradigm (model) for software architecture. </li></ul><ul><ul><li>Focus herein is “software & systems architecture” </li></ul></ul><ul><li>“ Services” are the central concept; other concepts are present. </li></ul><ul><li>SOA not currently defined other than a “common law” or “defacto” perception of what it is. </li></ul><ul><li>Perceptions for definition of SOA are vastly disparate. </li></ul>
  6. 6. What is a SOA Reference Model? <ul><li>Is a model for developing a range of Service Oriented Architectures and analysis/comparison thereof. </li></ul><ul><li>Is not architecture for a single implementation. This is very important to understand since things you may see in other architecture might not be present in the Reference Model. </li></ul><ul><li>Is a framework for understanding significant relationships among the elements of a SOA environment. </li></ul><ul><li>Is based on concepts present in all SOA’s. </li></ul><ul><li>A Reference Model defines SOA in an abstract sense. Example: </li></ul><ul><ul><ul><li>Abstract = Service Description </li></ul></ul></ul><ul><ul><ul><li>Concrete = WSDL </li></ul></ul></ul>
  7. 7. To develop a Reference Model for SOA <ul><li>The TC is asking itself these questions: </li></ul><ul><ul><li>What elements are common in all implementations of SOA? ( be careful – think about this) </li></ul></ul><ul><ul><li>(Paraphrased) What are the core things that make SOA service oriented? </li></ul></ul><ul><ul><li>How do we describe those as abstract concepts? </li></ul></ul><ul><ul><li>What relationships exist amongst those concepts? </li></ul></ul><ul><ul><li>How do we represent those concepts without referencing concrete implementations. </li></ul></ul>
  8. 8. Draft Conceptual SOA Reference Model
  9. 9. Base Components <ul><li>Service: A behavior, or set of behaviors provided for use by another entity . </li></ul><ul><li>Service Description: A specification of the information necessary to: </li></ul><ul><ul><li>allow a potential consumer to determine whether or not this service is applicable, and </li></ul></ul><ul><ul><li>facilitate invocation. </li></ul></ul><ul><li>Advertisement: A methodology to convey awareness of (the existence of) a service(s) to all consumers on a fabric. Advertising makes discovery possible. </li></ul>
  10. 10. Base Components and Concepts of SOA <ul><li>Data Model: The logical expression of a set of information items associated with the consumption of a service or services. </li></ul><ul><li>Contract: The syntactic,  semantic and logical constraints governing on the use of a service. </li></ul>
  11. 11. SOA Axioms <ul><li>A Service is a set of functionality provided by one entity for the use of others. </li></ul><ul><li>Services are conceptually autonomous (self sufficient) and opaque (independent of underlying technology) in nature. </li></ul><ul><li>There is no need to make architectural distinctions between services that are consumed as part of a process vs. ones that are not. </li></ul><ul><li>There is not always a one to one correlation between “on the wire” requests to invoke a service and service responses being consumed. </li></ul><ul><li>Each logical Service has exactly one canonical Service Description. </li></ul>
  12. 12. SOA Axioms <ul><li>A Service Description is comprised of three logical parts </li></ul><ul><ul><li>- Data Model - The logical expression of a set of information items associated with the consumption of a service or services; </li></ul></ul><ul><ul><li>- Policy - Assertions and obligations that service consumers and/or providers must adhere to or provide; and </li></ul></ul><ul><ul><li>- Contract (and/or offer thereof) - the syntactic, semantic and logical constraints governing on the use of a service. </li></ul></ul><ul><li>A security policy is a specialized type of the Service Description policy noted above. </li></ul><ul><li>Service Policy may mandate security requirements to be met, and if they are not, interaction (with the service) may be refused. </li></ul>
  13. 13. SOA Axioms <ul><li>A null security policy is still logically considered a policy. </li></ul><ul><li>A Service Description is advertised to consumers on a fabric to make it discoverable. </li></ul><ul><li>Discovery does not constitute authorization to execute against the service. </li></ul>
  14. 14. Agenda <ul><li>What is SOA; what is a reference model for SOA </li></ul><ul><li>Why is a reference model needed </li></ul><ul><li>The OASIS SOA RM TC </li></ul>
  15. 15. Existing situation WSDL XML & Schema SOAP Base Standards WS-RM WS Addressing Reg/Rep UDDI WS-Security WS-Trust WS-* Requirements Question: How do I account for my requirements and organize components when building a concrete architecture?
  16. 16. Thoughts on developing specific SOA’s <ul><li>Probably not logical to try and develop a “one size, fits all” architecture for SOA or WS. </li></ul><ul><li>Not rational to develop multiple architectures in standards bodies for every set of requirements. </li></ul><ul><li>Best solution: develop an SOA reference Model. </li></ul><ul><ul><li>Used by architects to guide development of specific service oriented architectures. </li></ul></ul><ul><ul><li>Model for a “way of thinking” when architecting. </li></ul></ul><ul><ul><li>Re-useable by multiple architects writing SOA for multiple domains. </li></ul></ul><ul><ul><li>Helps architects slot existing standards into their architectures. </li></ul></ul>
  17. 17. SOA RM used for range of architectures WSDL XML & Schema SOAP Base Standards WS-RM WS Addressing Reg/Rep UDDI WS-Security WS-Trust WS-* Requirements Guides developments of SOA-RM Specific Architectures Uses Input for
  18. 18. Agenda <ul><li>What is SOA; what is a reference model for SOA </li></ul><ul><li>Why is a reference model needed </li></ul><ul><li>The OASIS SOA RM TC </li></ul>
  19. 19. OASIS SOA Reference Model TC <ul><li>Chartered February 2005 </li></ul><ul><li>Problem to be solved : </li></ul><ul><ul><li>&quot;Service Oriented Architecture&quot; (SOA) as a term is being used in an increasing number of contexts and specific technology implementations, sometimes with differing or conflicting understandings of implicit terminology and components. </li></ul></ul><ul><ul><li>The proposal to establish a Reference Model is intended to encourage the continued growth of specific and different SOA implementations whilst preserving a common layer that can be shared and understood between those or future implementations. </li></ul></ul>
  20. 20. OASIS SOA Reference Model TC <ul><li>Purpose : </li></ul><ul><ul><li>The SOA-RM TC will deliver a Service Oriented Architecture Reference Model (SOA-RM). </li></ul></ul><ul><ul><li>The TC may also create sub-committees, promotional material, liaisons or other promulgation of the TC's work, in order to promote the use of the SOA Reference Model. </li></ul></ul><ul><ul><li>May help vertical industries develop SOA for their requirements. </li></ul></ul>
  21. 21. Charter Definition <ul><li>Reference Model: </li></ul><ul><li>A reference model is an abstract framework for understanding significant relationships among the entities of some environment, and for the development of consistent standards or specifications supporting that environment. A reference model is based on a small number of unifying concepts. A reference model is not directly tied to any standards, technologies or other concrete implementation details, but it does seek to provide a common semantics that can be used unambiguously across and between different implementations. </li></ul>
  22. 22. References <ul><li>OASIS SOA RM TC - http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=soa-rm </li></ul>
  23. 23. Other orientation activities <ul><li>Review member submissions in our document repository. </li></ul><ul><li>Review glossary - http://www.tekni.ca/twiki/bin/view/SoaRefModel/SoaReferenceModelGlossary </li></ul><ul><li>Review SOA axioms - http://www.oasis-open.org/apps/org/workgroup/soa-rm/download.php/12246/SOA%20Axioms.pdf </li></ul><ul><li>Review message archives. </li></ul>
  24. 24. Links to non-related Reference Models <ul><li>1. http://www.isotopicmaps.org/TMRM/TMRM-latest.html </li></ul><ul><li>Short and to the point. A good demonstration of how efficient and small a good reference model can be. </li></ul><ul><li>2. http://www.isotopicmaps.org/tmrm/rm20031014.pdf </li></ul><ul><li>A Mathematical formula of the above Reference Model for Topic Maps </li></ul><ul><li>3. http:// www.dpconline.org/docs/lavoie_OAIS.pdf </li></ul><ul><li>The OAIS Reference Model overview. Another good example of a small, compact, lean reference model. </li></ul><ul><li>4. http://www.x12.org/x12org/comments/X12Reference_Model_For_XML_Design.pdf </li></ul><ul><li>X12 reference model for XML. 120 pages – more technical. </li></ul><ul><li>5. http://www.digitalearth.gov/derm/v05/derm05.pdf </li></ul><ul><li>This reference model actually brings together implementation technologies with abstract concepts. </li></ul><ul><li>6. http://www.wfmc.org/standards/docs/tc003v11.pdf </li></ul><ul><li>Workflow Reference Model that includes specific technology – 55 pages </li></ul>

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