McLean, VA May 23, 2006 SOA: Reference Model, Standards and Specifications This document is confidential and is intended solely for the use and information

McLean, VAMay 23, 2006

SOA: Reference Model, Standards and Specifications

This document is confidential and is intended solely for the use and information of the client to whom it is addressed.

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Table of Contents

Service Oriented Architecture & Web Services

Reference Models as part of Service Oriented Architecture

OASIS SOA Reference Model

Standards within Service Oriented Architecture

Specifications and profiles in Service Oriented Architecture

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SOA is an integration paradigm that encourages organizations to re-think how their IT capabilities are organized

SOA is an architecture approach for organizing and using services to support interoperability between enterprise data

assets and applications

Capabilities performed by one for another to achieve a

desired outcome

ServiceS

The fundamental organization of a system by its capabilities,

their interactions, and the enterprise environment

ArchitectureA

Aligning architecture to enable a collection of services to be

linked together to solve a business problem

OrientedO

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SOA benefits uniquely address a rapidly changing environment

AgilityAgility

Focus more on core competencies and missions by creating a network of producers-suppliers with intense interactions

Improve access to information to enable faster cycle times

Enable enterprises to be more agile and respond quickly to business needs

Focus more on core competencies and missions by creating a network of producers-suppliers with intense interactions

Improve access to information to enable faster cycle times

Enable enterprises to be more agile and respond quickly to business needs

ProcessProcess

Increase business flexibility through plug-and-play architecture and re-use of existing services

Ensure system change is not a constraint on business or mission change

Allow interoperation with other systems & partners without customization

Increase business flexibility through plug-and-play architecture and re-use of existing services

Ensure system change is not a constraint on business or mission change

Allow interoperation with other systems & partners without customization

InteroperabilityInteroperability

Facilitate integration with multiple solutions via open IT standards

Remain platform, language, and vendor independent to remove IT barriers for using best-of-breed software packages

Facilitate integration with multiple solutions via open IT standards

Remain platform, language, and vendor independent to remove IT barriers for using best-of-breed software packages

CostsCosts

Reduce development costs by acquiring pre-built capabilities

Leverage previous IT investments through re-use of assets

Lower maintenance costs and TCO through fewer “instances” of a function, and fewer software licenses

Reduce development costs by acquiring pre-built capabilities

Leverage previous IT investments through re-use of assets

Lower maintenance costs and TCO through fewer “instances” of a function, and fewer software licenses

IT alignment with an organization’s missionIT alignment with an organization’s mission

Improved agility, focus on core competencies, IT efficiencies, and ROI for IT assetsImproved agility, focus on core competencies, IT efficiencies, and ROI for IT assets

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SOA allows end-to-end flexibility in meeting user needs

Web Services provide standard interfaces between disparate systems

DatabaseNetworkDataUser

Power PlantDVD Player Electric Outlet Power GridElectricity

Web Service

Consumer Product Service Interface Infrastructure Provider

Po

wer

SO

A

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Web services are a tactical means to achieve the strategic SOA goal

Web Services are a technical solution to enable SOA

SOA codifies the organization’s enterprise strategy for connecting systems to provide common discovery, security, and management of those connections

Web services have specific guidelines on messaging interactions between services – the tactical implementation of an SOA model

Thus, Web Services are a specific subset of how an SOA can be implemented

SOA

Web Services

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SOA transactions require answering five key questions

1. How can the Consumer dynamically discover the existence of a Provider, which can provide the services being requested?

2. Assuming the Consumer knows of the Provider’s existence, how can it locate the Provider?

3. Assuming the Consumer has located the Provider, how can the two describe how to connect to each other, in a standard format which can be understood regardless of their IT platforms?

4. Assuming they have described themselves, how can they exchange messages in a common messaging format which is independent of their underlying platforms?

5. Assuming they have agreed upon a common messaging format, what data format can they use to exchange data independent of their underlying database technologies?

Application 1“Service Consumer”

Application 2“Service Provider”

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Foundation for SOA implementations: a reference model, reference architectures, standards and specifications

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What is a reference model?

Minimal set of unifying concepts, axioms and relationships within a particular problem domain

Abstract framework for understanding significant relationships among the entities of some environment

Independent of specific standards, technologies, implementations, or other concrete details

Content Courtesy: Ken Laskey, MITRE

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How a reference model complements other architecture concepts

Reference Architecture - abstract solutions (using concepts from housing RM) to the problems of providing housing

– General pattern for housing that addresses the needs of some set of occupants

– Eating area is a reference model concept, a kitchen is a realization of eating area in the context of the reference architecture

– More than one reference architecture addresses requirements for developing solutions

Large apartment complexes – compact kitchen

Suburban single family houses – large kitchen

Dormitories – common kitchen

Space stations – specially-equipped kitchen


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The OASIS Service-Oriented Architecture Reference Model Technical Committee (SOA-RM TC) was chartered in February 2005

Charter: Developing a core reference model to guide and foster the creation of specific, service-oriented architectures

Objectives: Publish a reference model for SOA. Publish a reference Service Oriented Architecture that tracks to the reference model

Home page: http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=soa-rm

– See “Documents” section for latest version of specification

Participating organizations include:

– Adobe - Computer Associates– BEA - Department of Homeland Security– Boeing - Fujitsu– Booz Allen Hamilton- Lockheed Martin– Cap Gemini - Mitre Corporation

The TC is preparing for a second public review of the document

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SOA-RM – Goals and motivations

Why develop SOA-RM?

– SOA has received significant attention within the software design and development community

– Proliferation of many conflicting definitions (or simply imprecise use) of SOA

What intend to provide?

– Common conceptual framework that can be used consistently across and between different implementations

– Common semantics that can be used unambiguously in modeling specific solutions

– Unifying concepts to explain and underpin a generic design template supporting a specific SOA

– Definitions that should apply to all SOA


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Users of the SOA-RM

Architects and developers designing, identifying or developing a system based on the service-oriented paradigm

Standards architects and analysts developing specifications that rely on service oriented architecture concepts

Decision makers seeking a "consistent and common" understanding of service oriented architectures

Users who need a better understanding of the concepts and benefits of service oriented architecture


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The OASIS SOA Reference Model is centered around the notions of “needs” and “capabilities”

SOA is “a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains” (OASIS SOA Reference Model Committee Draft)

Entities (people and organizations) create capabilities to solve or support a solution for the problems they face in the course of their business

– Just as one person’s needs may be met by capabilities offered by someone else

There is not necessarily a one-to-one correlation between needs and capabilities

– The granularity of needs and capabilities are driven by the business, therefore they vary from fundamental to complex

– Any given need may require the combining of numerous capabilities, while any single capability may address more than one need

Examples: Using a hammer, purchasing a house

The perceived value of SOA is that that it provides a powerful framework for matching needs and

capabilities, and for combining capabilities to address those needs

The perceived value of SOA is that that it provides a powerful framework for matching needs and

capabilities, and for combining capabilities to address those needs

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The OASIS SOA reference model – Central concepts

Service

Dynamics of Services

– Visibility

– Interacting with services

– Real World Effect

About services

– Service description

– Policies and Contracts

– Execution context

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The OASIS SOA reference model – Central concepts

Service

Dynamics of Services

– Visibility

– Interacting with services

– Real World Effect

About services

– Service description

– Policies and Contracts

– Execution context

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Service description Represents the information needed

in order to use a service

Facilitate visibility and interaction between participants in service interactions

No one “right” description

– Elements of description required depend on the context and the needs of the parties using the associated entity

– Certain elements that are likely to be part of any service description (e.g the information mode) but many elements such as function and policy may vary

Best practice suggests that the service description SHOULD be represented using a standard, referenceable format

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Service Description – What goes into it Service description makes available critical information that a consumer needs to decide

whether or not to use a service

1. That the service exists and is reachable

2. That the service performs a certain function or set of functions

3. That the service operates under a specified set of constraints and policies

4. That the service will (to some implicit or explicit extent) comply with policies as prescribed by the service consumer

5. How to interact with the service in order to achieve the required objectives, where how-to information includes

1.the format and content of information exchanged

2.the sequences of information exchange that may be expected

1. Each of these items SHOULD be represented in any service description

1. Details can be included through references (links) to external sources and are NOT REQUIRED to be incorporated explicitly

2. Inclusion by reference enables reuse of standard definitions, such as for functionality or policies

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Standardization plays a key role in realization of SOA architectural characteristics

Benefits

• Leverages existing IT investments• Break down data silos• Promote agile business practices to meet changing business needs

• Emphasis on business logic and less on plumbing• Reuse functions both internally and externally • Bring new functionality online without disrupting existing business

• Reduce resources needed to complete existing work• Increased cross-organizational information visibility• Abstract heterogeneity

“An architecture is the fundamental organization of a system embodied in its components, their relationships to each other, and to the environment, and the principles guiding its design and evolution.” IEEE STD 1471-2000

Characteristics

High Interoperability

Loose Coupling

Location Transparency

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Open standards play a key role in shaping today’s SOA landscape

A standard is a set of detailed technical guidelines that establishes uniformity

Define a shared meaning that can drive commoditization of services

– Reflects horizontal requirements from a generic problem domain

– Considers broader applications and process models

– Encourages levels of interoperability

Characteristics

– Publicly available

– Developed by a process which sought a high level of consensus from a wide variety of sources

– Supported by a range of readily available products

“Open standards are important to help create interoperable and affordable solutions for everybody.” (Source: Erkki Liikanen World Standards Day, 14 October 2003)

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Several industry consortia develop standards to shape the technology landscape

World Wide Web Consortium (W3C):

W3C was created in October 1994 to lead the World Wide Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability

Organization for the Advancement of Structured Information Standards (OASIS):

OASIS is a not-for-profit, global consortium that drives the development, convergence, and adoption of e-business standards

Web Services Interoperability Organization (WS-I) :

WS-I is an open, industry organization chartered to promote Web services interoperability across platforms, operating systems, and programming languages

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Web Services standards are still emerging and being adopted by business

Source: Gartner

= In place

Format

Transport

Message

Description

Search & Find

Process Interaction

User Interface

Building Trust

Identity Mgmt

BusinessSemantics

Common internet protocols (TCP/IP, HTTP, etc)

Extensible Markup Language (XML)

SOAP

Web Services Definition Language (WDSL)

Universal Description, Discovery & Integration (UDDI)

WS-Transaction, BPEL4 WS, WSCI

Liberty, Passport

WS-Security, Security Assertions Markup Language (SAML)

Web Services for Remote Portals (WSRP), Web Services User Interface (WSUI)

StandardNeed

Emerging

Established

Entrenched

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How do web services know where to “locate” another web service?

Web Service standards today address key SOA-RM concepts

Key QuestionKey Question Nature of Standards Required

Nature of Standards Required StandardsStandards

How can web services dynamically “discover” the existence of other web services?

Standard method for defining and identifying web services

Public registry of web services and their locations, which can be queried by any web service over HTTP

Standard method for defining and identifying web services

Public registry of web services and their locations, which can be queried by any web service over HTTP

Universal Discovery, Description and Integration (UDDI)

Universal Discovery, Description and Integration (UDDI)

How can web services universally “describe” how to connect to themselves ?

How can web services universally “describe” how to connect to themselves ?

Standard language to describe how to connect to a web service

Standard language to describe how to connect to a web service

Web Services Description Language (WSDL)

Web Services Description Language (WSDL)

What “data formats” can web services universally use?

What “data formats” can web services universally use?

Standard data format transportable over Internet protocols

Standard data format transportable over Internet protocols



What “messaging formats” can web services universally use?

What “messaging formats” can web services universally use?

Standard messaging format which conveys instructions on what to do with the data

Standard messaging format which conveys instructions on what to do with the data

SOAP SOAP

SOA-RM ConceptSOA-RM Concept

VisibilityVisibility

Service DescriptionService Description

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Key standards work together to realize web services interaction

1

2

3

5 8

High Level DescriptionHigh Level Description

Web Service Provider (Provider) develops its description and specifies its interfaces using WSDL, and registers itself in the public UDDI registry

Web Service Consumer (Consumer) queries the UDDI registry in real time, and discovers that Provider has services it is looking for

Consumer downloads Provider’s WSDL specification from the Provider (including the format of SOAP messages the Provider can accept)

Consumer then develops a request in the form of an XML based SOAP message (using a SOAP engine to translate from its native format to SOAP)

Consumer then “calls” Provider by sending the SOAP message over HTTP

Provider receives the SOAP message and translates to its own native format using a SOAP decoder

Provider composes a reply as a SOAP message in a format which can be understood by Consumer (the incoming SOAP message from Consumer also includes information on the format of SOAP messages it can accept)

Provider then “replies” to Consumer by sending the SOAP message over HTTP

Web Service Provider (Provider) develops its description and specifies its interfaces using WSDL, and registers itself in the public UDDI registry

Web Service Consumer (Consumer) queries the UDDI registry in real time, and discovers that Provider has services it is looking for

Consumer downloads Provider’s WSDL specification from the Provider (including the format of SOAP messages the Provider can accept)

Consumer then develops a request in the form of an XML based SOAP message (using a SOAP engine to translate from its native format to SOAP)

Consumer then “calls” Provider by sending the SOAP message over HTTP

Provider receives the SOAP message and translates to its own native format using a SOAP decoder

Provider composes a reply as a SOAP message in a format which can be understood by Consumer (the incoming SOAP message from Consumer also includes information on the format of SOAP messages it can accept)

Provider then “replies” to Consumer by sending the SOAP message over HTTP

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2

3

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5

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7

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Application 1“Service Consumer”

Application 2“Service Provider”

UDDI Service Registry

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Specifications: Harmonize standards within an architecture context

Define fundamental functionality– What standards address the capabilities and requirements?

– What are the communication patterns?

Stipulate interfaces as selection of options within a set of standards– What are the public interfaces for the service?

– What are the calling mechanisms?

Address dependencies between functionality and interfaces– What are the significant architectural decisions to analyze?

– What are the dependencies and interrelationships between applicable standards?

A specification defines the interfaces thru which existing standards (or set of standards) are applied as a solution to a particular integration challenge

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Service specifications bring together standards as part of a technical solution to a business problem

Service specifications establish architectural requirements, document functionality to support them, and identify the standards which facilitate

– Encourage implementation of appropriate information technology to meet business needs

– Consider organization-specific requirements, implementations, and business rules

– Aggregate applicable standards into cohesive units of functionality

– Harmonize standards to achieve a particular architectural goal

Reference Architecture

Reference Model

Messages

XML(standard data representation)

SOAPHeaders, Body & Extensions

DescriptionsWeb Service Interfaces (WSDL)

ProcessesDiscovery, Aggregation, Choreography

Communications & Standards Networking Layer

MA

NA

GE

ME

NT

SE

CU

RIT

Y(A

uthentication, Authorization, P

olicy…)

Specification Based Architecture

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A specification describes a capability defined by the architecture

Describe and communicate, in varying levels of abstraction, the context in which a service operates; the boundaries across which interaction occurs; meanings that are described in terms of observable effects

Information Model

(The information exchanged)

Describe the capability provided by the service in terms of inputs and outputs

Describes the expected input and output data model Outlines the available metadata for the service that will be published and searchable

Interface Model

(That the service exists)

Describes the interface

Describes available operations

Describes any faults that may be generated by an individual operation

Behavior Model

(How to interact with the service)

How the service interacts with other services

Describes the underlying processing rules of the service

Describes the multiple integration patterns available to use this service

Fault Model

(How the service fails)

Describes how the service will handle faults

Describe under which conditions a fault may be returned to the consumer

Quality Model

(Constraints and policies)

Describes the security requirements of the service

Describe the quality of service provided

Describes any performance considerations for deploying the service

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How should I apply this knowledge to my organizations SOA initiatives?Start today, be decisive, and follow a methodology

Formulate SOA Solution Strategy

Build SOA Business Case

Establish Program

Management

Architect SOA Solution

Operate SOA Environment

Implement SOA Solution

SOA Methodology

Perform technology portfolio assessment• Evaluate current technology environment and

build a service portfolio• Determine SOA related criteria for services

portfolio analysis• Complete portfolio analysis to establish service

fielding priorities• Develop a SOA roadmap and strategic guidance

Develop business case to support SOA investment

• Support SOA strategy with rigorous business case analysis

• Establish pertinent business case metrics• Account for cost, ROI, and risk

management in SOA investment decisions

1

2

3

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Develop and implement change management strategy • Engage stakeholders continuously• Create needed collaborations and governance structures• Incentivize participation • Identify progress metrics and milestones• Reinforce organizational changes• Establish management controls

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Acknowledgements

SOA-RM Editors

– C. Matthew MacKenzie, Adobe Systems Incorporated, [email protected]

– Ken Laskey, MITRE Corporation, [email protected]

– Francis McCabe, Fujitsu Limited, [email protected]

– Peter Brown, [email protected]

– Rebekah Metz, Booz Allen Hamilton, [email protected]

Other members of the SOA-RM TC here

– Chris Bashioum, MITRE, [email protected]

– Joe Chiusano, Booz Allen Hamilton, [email protected]

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Questions?

Rebekah Metz

Booz Allen Hamilton

Telephone: 703.377.1471Email: [email protected]