SOA Reference Model

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SOA Reference Model

• Generic Presentation

DRAFT Not approved by the OASIS SOA RM TC.
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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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In order define SOA

• If SOA is Architecture, as the name implies, it
  should be definable as architecture.
• We should not do it by referencing an
  implementation.
• DEFINITION (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 developing
  architecture.
• Focus herein is software systems architecture
• Services are the central concept, yet other
  concepts are present in all implementations.
• Is not currently defined other than a common
  law or defacto perception of what it is.
• Perceptions of what SOA is vastly disparate.

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SOA Reference Model...

• Is not architecture for a single implementation.
• Is a model for developing a range of Service
  Oriented Architectures and analysis/comparison
  thereof.
• Is a framework for understanding significant
  relationships among the entities in a SOA
  environment.
• DISCUSSION POINT should the word elements be
  used in place of entities above?
• Is based on a small number of unifying concepts
  of all SOAs.
• A Reference Model is the best mechanism to define
  SOA.

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To develop a Reference Model for SOA

• Ask questions
• What elements are common in all implementations
  of SOA? ( be careful think about this )
• What abstract concepts do those elements
  represent?
• What relationships exist amongst those concepts?
• How do we represent those concepts without
  referencing concrete implementations.
• How does this relate to infrastructure concepts?

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Draft Candidate SOA Reference Model
DISCUSSION POINT Details of how to interpret
Concept Maps are included in the position
paper submitted by Mackenzie, Nickull.
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Base Components and Concepts of SOA

• Service A service is a contractually defined
  behavior that can be implemented and provided by
  a component for use by any component solely based
  on the contract.
• Service Description Technical parameters,
  constraints, policies that come together to
  define terms of invocation.
• DISCUSSION POINT Is the contract part of the
  service description or referenced from it (if
  explicit)? The contract is shown linked to the
  service since it may be implied only and not
  physically able to be linked via a Service
  Description..
• Advertising Makes all potential or intended
  consumers of a service on a fabric aware that the
  service exists. This MAY involve advertising the
  Service Description.

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Base Components and Concepts of SOA

• Data Model The specification and constraints
  imposed on instance data.
• QUESTION Are semantics part of the data model?
  If not, how to others know what data model
  authors really mean?
• Contract The implicit or explicit bi-lateral or
  multi-lateral agreement between the owners or
  agents of a service and those who use the
  service.
• QUESTION Is no contract still ipso facto a
  contract? Is zero a number or null a value?

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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 map my Requirements to
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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Developing SO Architecture

• 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 service oriented
  architecture development.
• Model for a way of thinking when developing
  solutions.
• 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
QUESTION Does this adequately explain the need
for a reference model? Does this also clarify
why a reference model is better than developing
multiple 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