OASIS Service Oriented Architecture Reference Model Technical Committee SOARM

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OASIS Service Oriented Architecture Reference
Model Technical Committee (SOA-RM)

• BOOT CAMP
• April 13 2005

DRAFT Not approved by the OASIS SOA RM TC.
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Purpose

• This slide deck is designed to bring new TC
  members up to speed.
• Work described herein defines what we have
  consensus on at present time.
• CAVEAT Subject to change in future

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Agenda

• What is SOA what is a reference model for SOA
• Why is a reference model needed
• The OASIS SOA RM TC

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Defining SOA

• If Service Oriented Architecture is Architecture,
  as the name implies, it should be definable as
  architecture.
• This should not be done by referencing specific
  implementations.
• Definition of Architecture (from Charter)
• 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.

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Closer look Service Oriented

• Is a paradigm (model) for software architecture.
• Focus herein is software systems architecture
• Services are the central concept other
  concepts are present.
• SOA not currently defined other than a common
  law or defacto perception of what it is.
• Perceptions for definition of SOA are vastly
  disparate.

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What is a SOA Reference Model?

• Is a model for developing a range of Service
  Oriented Architectures and analysis/comparison
  thereof.
• 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.
• Is a framework for understanding significant
  relationships among the elements of a SOA
  environment.
• Is based on concepts present in all SOAs.
• A Reference Model defines SOA in an abstract
  sense. Example
• Abstract Service Description
• Concrete WSDL

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To develop a Reference Model for SOA

• The TC is asking itself these questions
• What elements are common in all implementations
  of SOA? ( be careful think about this)
• (Paraphrased) What are the core things that
  make SOA service oriented?
• How do we describe those as abstract concepts?
• What relationships exist amongst those concepts?
• How do we represent those concepts without
  referencing concrete implementations.

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Draft Conceptual SOA Reference Model
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Base Components

• Service A behavior, or set of behaviors provided
  for use by another entity.
• Service Description A specification of the
  information necessary to
• allow a potential consumer to determine whether
  or not this service is applicable, and
• facilitate invocation.
• Advertisement A methodology to convey awareness
  of (the existence of) a service(s) to all
  consumers on a fabric. Advertising makes
  discovery possible.

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Base Components and Concepts of SOA

• Data Model The logical expression of a set of
  information items associated with the consumption
  of a service or services.
• Contract The syntactic,  semantic and logical
  constraints governing on the use of a service.

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SOA Axioms

• A Service is a set of functionality provided by
  one entity for the use of others.
• Services are conceptually autonomous (self
  sufficient) and opaque (independent of underlying
  technology) in nature.
• There is no need to make architectural
  distinctions between services that are consumed
  as part of a process vs. ones that are not.
• There is not always a one to one correlation
  between on the wire requests to invoke a
  service and service responses being consumed.
• Each logical Service has exactly one canonical
  Service Description.

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SOA Axioms

• A Service Description is comprised of three
  logical parts
• - Data Model - The logical expression of a set
  of information items associated with the
  consumption of a service or services
• - Policy - Assertions and obligations that
  service consumers and/or providers must adhere to
  or provide and
• - Contract (and/or offer thereof) - the
  syntactic, semantic and logical constraints
  governing on the use of a service.
• A security policy is a specialized type of the
  Service Description policy noted above.
• Service Policy may mandate security requirements
  to be met, and if they are not, interaction (with
  the service) may be refused.

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SOA Axioms

• A null security policy is still logically
  considered a policy.
• A Service Description is advertised to consumers
  on a fabric to make it discoverable.
• Discovery does not constitute authorization to
  execute against the service.

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Agenda

• What is SOA what is a reference model for SOA
• Why is a reference model needed
• The OASIS SOA RM TC

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Existing situation
Question How do I account for my requirements
and organize components when building a
concrete architecture?
Requirements
WS-
WS-Security
WSDL
WS-Trust
XML Schema
Base Standards
SOAP
WS Addressing
WS-RM
UDDI
Reg/Rep
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Thoughts on developing specific SOAs

• Probably not logical to try and develop a one
  size, fits all architecture for SOA or WS.
• Not rational to develop multiple architectures in
  standards bodies for every set of requirements.
• Best solution develop an SOA reference Model.
• Used by architects to guide development of
  specific service oriented architectures.
• Model for a way of thinking when architecting.
• Re-useable by multiple architects writing SOA for
  multiple domains.
• Helps architects slot existing standards into
  their architectures.

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SOA RM used for range of architectures
SOA-RM
Guides developments of
Specific Architectures
Requirements
Input for
Uses
WS-
WS-Security
WSDL
WS-Trust
XML Schema
Base Standards
SOAP
WS Addressing
WS-RM
UDDI
Reg/Rep
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Agenda

• What is SOA what is a reference model for SOA
• Why is a reference model needed
• The OASIS SOA RM TC

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OASIS SOA Reference Model TC

• Chartered February 2005
• Problem to be solved
• "Service Oriented Architecture" (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.
• 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.

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OASIS SOA Reference Model TC

• Purpose
• The SOA-RM TC will deliver a Service Oriented
  Architecture Reference Model (SOA-RM).
• 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.
• May help vertical industries develop SOA for
  their requirements.

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Charter Definition

• Reference Model
• 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.

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References

• OASIS SOA RM TC - http//www.oasis-open.org/commit
  tees/tc_home.php?wg_abbrevsoa-rm

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Other orientation activities

• Review member submissions in our document
  repository.
• Review glossary - http//www.tekni.ca/twiki/bin/vi
  ew/SoaRefModel/SoaReferenceModelGlossary
• Review SOA axioms - http//www.oasis-open.org/apps
  /org/workgroup/soa-rm/download.php/12246/SOA20Axi
  oms.pdf
• Review message archives.

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Links to non-related Reference Models

• 1. http//www.isotopicmaps.org/TMRM/TMRM-latest.ht
  ml
• Short and to the point. A good demonstration of
  how efficient and small a good reference model
  can be.
• 2. http//www.isotopicmaps.org/tmrm/rm20031014.pdf
  
• A Mathematical formula of the above Reference
  Model for Topic Maps
• 3. http//www.dpconline.org/docs/lavoie_OAIS.pdf
• The OAIS Reference Model overview. Another good
  example of a small, compact, lean reference
  model.
• 4. http//www.x12.org/x12org/comments/X12Reference
  _Model_For_XML_Design.pdf
• X12 reference model for XML. 120 pages more
  technical.
• 5. http//www.digitalearth.gov/derm/v05/derm05.pdf
  
• This reference model actually brings together
  implementation technologies with abstract
  concepts.
• 6. http//www.wfmc.org/standards/docs/tc003v11.pdf
  
• Workflow Reference Model that includes specific
  technology 55 pages