Service-Oriented Architecture (SOA)

Copyright © 2005, Systems and Software Consortium, Inc.

www.systemsandsoftware.org

Service-Oriented Architecture (SOA)

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Topics

Sec.TOPICS

55. The Road Ahead44. How Does It Work?33. Benefits22. What is SOA?11. The Setting



The Setting

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What’s the Problem?

• Increasing Complexity• Legacy Applications• Stovepipes – Islands of Automation• Linkage between Strategic Intent and

Information Technology (IT)• Lock-In: Platform, Technology, Vendor• Cost of IT• Time to Market• Success!?!?

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What Do You Want?

• Extend the value chain to suppliers and customers (citizens)

• Respond to change quickly and effectively• Reduce IT costs• Get more bang for the buck from IT

investments• Get everything to work well together

(integration)



What is SOA?

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What Is SOA?

•SOA is an architectural style whose goal is to achieve loose coupling among interacting services

•It is a way to organize and use capabilities that may be under the control of different owners.

•It provides a uniform means to offer, discover, interact with, and use capabilities without having to know all of the underlying technical details.

vanes

Would say that "Loose Coupling" is a means whereby SOA can achieve its goal, but not the goal itself. Isn't the ultimate goal more about business agility in the computing environment and aligning IT with the overall goals of the enterprise, also, realizing better scalability and interoperability and long term profit/success even in spite of future changes?

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What Distinguishes SOA?

• Reusability• Loose Coupling• Discoverability• Abstraction• Composability

vanes

Coarse-grained servicesMessage-oriented processingBusiness Process Orchestration - even long termScalabilityInteroperability

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• Enterprise Architecture• Web Services• Middleware• Client/Server Architecture• Object-Oriented Programming• Distributed Computing• IT-only

SOA is Not…

goodhart

Put comments on why some of these are not SOA into the speaker's notes

Brian Goodhart

- I still think the "why" of each of these belongs in the speaker's notes. We can ask a third party if you feel strongly about it.- It might be "Enterprise Application Integration," but in any case EA <> EAI, so I added EA back in.

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SOA is Not Client-Server

No Dynamic Discovery – all interactions known in advance

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SOA is Not DCOM

• Proprietary and platform dependent• Application level not business level

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Service-Oriented Architecture (SOA)SOA is Not Classic Mainframe

Environment• Platform dependent• Tightly-coupled

Mainframe

• Operating System• User Interface• DBMS• Communications

TerminalTerminal

Terminal

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SOA is Not Common Request Broker Architecture (CORBA)

• Doesn’t address business processes or business process interoperability

• Broker-based, not message-based• Not flexible enough• Highly structured data• Too complex

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SecurityServices

MonitoringServices

ServiceRegistries

MessagingServices

DataServices

TransformationServices

Service Enabled InfrastructurePublish

Data and applications available for use, accessible via services. Metadata added to services based on producer’s format.

Service Producer

• Describes content using metadata• Posts metadata in catalogs for discovery• Exposes data and applications as services

Discover

Invoke

Automated search of data services using metadata. Pulls data of interest. Based on producer registered format and definitions, translates into needed structure.

Service Consumer

• Searches metadata catalogs to find data services

• Analyzes metadata search results found• Pulls selected data based on metadata

understanding

SecurityServices

MonitoringServices

ServiceRegistries

MessagingServices

DataServices


Service Enabled Infrastructure

SecurityServices

MonitoringServices

ServiceRegistries

MessagingServices

MessagingServices

DataServices

DataServices


Service Enabled InfrastructurePublishPublish


Service Producer



Service Producer


DiscoverDiscover

InvokeInvoke


Service Consumer



understanding


Service Consumer



understanding

e.g. Web Services

An Example Implementation of SOA



Benefits

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Benefits

• Reduced risk from standards-based frameworks• Reduced development cost • Accelerated development • Increased responsiveness• Leveraged existing IT assets via “exposure” as

reusable services

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Benefits: The Bottom Line

• The main drivers for SOA-based architectures are to facilitate the manageable growth of large-scale enterprise systems, to facilitate Internet-scale provisioning and use of services and to reduce costs in organization-to-organization cooperation.

• The concepts used in SOA are not new, but using them to align the business strategies together with IT initiatives is.



How Does It Work?

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Service

• A service in SOA is like a web site for machines instead of people

• A service is a composable, universally accessible function with:– The capability to perform work for

another– The specification of the work offered for

another– The offer to perform work for another

• Needs and capabilities exist independent of SOA

• Services are the mechanism whereby needs and capabilities are brought together

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The Dichotomy of a Service

Consumer (traveler) has a Need (transportation)

Provider (carrier) has a Capability (flight)

goodhart

Consumer/Provider dichotomy?

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Example SOA Network

Source: http://www.optaros.com/pdf/wp_AMichelson_SOA_OSS.pdf

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Service-Oriented Architecture (SOA)Functional Regions of an SOA

Architecture

http://www.optaros.com/pdf/wp_AMichelson_SOA_OSS.pdf



The Road Ahead

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Real World Challenges

• Education• Hype, buzzwords and tools• Alignment with business needs • High initial cost• Adaptation of large silo-based enterprise

solutions• Security• Testability • Governance

vanes

Biggest chanllenge is getting exec mgt to drive SOA such that the overarching goals of the enterprise are addressed and not the goals of individual fiefdoms within the enterprise. A department manager could wipe out major benefits of SOA by diligently pursuing their own goals at the expense of what SOA is trying to achieve.

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Best Practices

• Take a top-down approach • Start small (one service) • Target evolutionary transition, not

revolutionary• Don’t wait for standards – just do it and

focus on interoperability • Keep it loosely coupled and “coarsely

grained”• Build infrastructure only as required to

support the current application being developed

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Standards

Organization for theAdvancement ofStructuredInformationStandards(http://www.oasis-

open.org)

• 1993• Non-profit• International• > 5000 participants• > 600 organizations• > 100 countries

Reference Model for Service

Oriented Architecture 1.0• Public Review Draft 2• 31 May 2006• Identifier: wd-soa-rm-pr2• Encourage the continued growth

of different and specialized SOA implementations whilst preserving a common layer of understanding about what SOA is

Service-Oriented Architecture (SOA)

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