Architecture, Styles, and Service Oriented Architecture

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Architecture, Styles, and Service Oriented
Architecture

• Richard Osborne
• September 22, 2006

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Architecture Defined

• the art of creating an actual, implied or
  apparent plan of any complex object or system
• a subjective mapping from a human perspective to
  the elements or components of some kind of
  structure or system, which preserves the
  relationships among the elements/components

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IT or Systems Architecture

• Many definitions
• the representation of an engineered system, and
  the process and discipline for effectively
  implementing the design(s) for such a system.
  Such a system may consist of information and/or
  hardware and/or software
• The fundamental organization of a system,
  embodied in its components, their relationships
  to each other and the environment, and the
  principles governing its design and evolution.
  From ANSI/IEEE 1471-2000

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IT or Systems Architecture

• A representation of a system in which there is a
  mapping of functionality onto hardware and
  software components, a mapping of the software
  architecture onto the hardware architecture, and
  human interaction with these components. From the
  Carnegie Mellon University's Software Engineering
  Institute
• An architecture description is a formal
  description of a system, organized in a way that
  supports reasoning about the structural
  properties of the system. It defines the system
  components or building blocks...and provides a
  plan from which products can be procured, and
  systems developed, that will work together to
  implement the overall system. It thus enables you
  to manage...investment in a way that meets
  business needs. From The Open Group
  Architecture Framework

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IT or Systems Architecture

• All have some common elements
• Structure
• Components
• Relationships
• Purpose
• Plan

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Enterprise Architecture

• Applying IT Architecture disciplines to an
  enterprise
• Outside-in, strategy-driven, top-down viewpoint
• Alignment the holy grail
• the practice of applying a comprehensive and
  rigorous method for describing a current and/or
  future structure and behavior for an
  organization's processes, information systems,
  personnel and organizational sub-units, so that
  they align with the organization's core goals and
  strategic direction

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Enterprise Architecture

• FEA Federal Enterprise Architecture
• Core Principles
• Business-driven
• Proactive collaborative across the Federal
  government
• Architecture improves the effectiveness and
  efficiency of government information resources
• No IT investment without a business-approved
  architecture

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Enterprise Architecture

• Alignment of business strategy IT investments
• Architecture is the translation of business
  strategy into technical strategy
• Use of a framework to
• Document current state
• Define the future state desired capabilities
• Create a roadmap to get there
• There are many reference frameworks
• Zachman
• FedArch
• E2A
• TOGAF

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Enterprise Architecture

• All have some combination of the following
  concepts

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Reference Architecture

• Reference architecture - a style or method
• a coherent design principle used in a specific
  domain
• describes the kinds of system components, their
  responsibilities, dependencies, possible
  interactions, and constraints.
• basis for designing the system architecture for a
  particular system.
• the architect can select from a set of well-known
  elements (standard parts) and use them in ways
  appropriate to the desired system architecture

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Reference Architecture

• Pre-defined architectural pattern
• Designed and proven for use in particular
  business and technical contexts
• Often harvested from previous projects
• Best practices
• Abstract solutions from many previous attempts
• Example - Open System Interconnection model
  defines a networking framework for implementing
  protocols in seven layers

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Service Oriented Architecture

• A collection of services that communicate with
  each other
• A service is a function that is well-defined,
  self-contained and does not depend on the context
  or state of other services
• From simple data passing to two or more services
  coordinating (orchestrating) some activity
  (business process)
• Not a new concept

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Service Oriented Architecture
Service Oriented Business Applications (Loosely
Coupled, Business Services as Assets)
Application Silos with Components (Tightly
Coupled and Limited Reuse)
Service Oriented Architecture
Monolithic Architecture (Tightly Coupled,
Application Silos)
Component Based Architecture
Monolithic Architecture
Time
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Service Oriented Architecture
Next stage of integration
Services (SOA)
Whats Next?
Business Process Management
EAI
Message Processing
Remote Object Invocation
Sub-routines Remote Procedure Calls
Monolithic Architectures
Pre 50s - 60s
70s - mid 80s
80s - Mid 90s
Mid 90s to Early 00s
Today
Future
Late 90s
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Why is Integration Important?

• Investments made in legacy systems
• Trillions of over the past 40 to 50 years
• Remember Y2K?
• Mainframe
• Distributed Client-Server
• Web
• Application Packages such as ERP
• Cost and Time to develop deploy new business
  functionality
• Rates from 30/hour (off-shore) to 300/hour
• A small 5 person year project (10,000 hours) can
  easily cost in excess of 2M and take a year to
  deliver

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Why is Integration Important?

• Why develop a new system/business function when
  you already have it?
• Is it locked up in a different technology?
• The cost to maintain two of the same is not 2X
  but 3X .. Or more
• SOA is a way to re-use the assets that most
  organizations already own
• Break down the existing systems into components
  that can be combined in new ways
• A flexible, standards-based integration method is
  needed

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Why is Integration Important?
SOI
EAI
SOI integrates applications platforms using
service interactions an ESB is the least
brittle for changes.
EAI uses broker-specific adaptors which provide
pre-built connectivity to a wide variety of
applications platforms less brittle for
changes than P2P.
Custom Point-to-Point Integration uses technology
aware bridges between application components
very brittle for changes.
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How do we achieve integration?

• The Silo monolithic architecture

User Interface
Business Logic
Data Access
Data
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How do we achieve integration?

• Separation of Concerns

User Interface
Integration Layer
Business Logic
Integration Layer
Data Access
Integration Layer
Data
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SOA Definitions - Viewpoints

• a set of services that a business wants to expose
  to their customers and partners, or other
  portions of the organization
• an architectural style which requires a service
  provider, requestor and a service description
• a set of architectural principles, patterns and
  criteria which address characteristics such as
  modularity, encapsulation, loose coupling,
  separation of concerns, reuse, compose-ability
  and single implementation
• a programming model complete with standards,
  tools and technologies such as Web Services

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SOA Reference Architecture
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SOA's Standards Foundation

• BPEL (Business Process Execution Language) a
  standard for assembling sets of discrete services
  into an end-to-end business process
• J2EE 1.4 the current version of Java 2 Platform,
  Enterprise Edition, with APIs for deploying and
  managing Web services
• JSR 168 standard for portal and portlet
  interoperability
• JSR 181 an API for Web services metadata
  annotation
• SOAP (Simple Object Access Protocol) a
  W3C-approved standard for exchanging information
  among applications
• UDDI (Universal Description, Discovery, and
  Integration) an OASIS-approved standard
  specification for defining Web service registries
  
• WS-I (Web Services Interoperability) an open
  industry organization promoting Web services
  interoperability across platforms, operating
  systems, and languages
• WS-Reliability (Web Services Reliability) a
  SOAP-based protocol for exchanging SOAP messages,
  with delivery and message-ordering guarantees
• WS-Security (Web Services Security) a SOAP-based
  protocol that addresses data integrity,
  confidentiality, and authentication in Web
  services
• WSDL (Web Service Description Language) a
  W3C-approved standard for using XML to define Web
  services
• WSIF (Web Services Invocation Framework) an open
  source standard for specifying, in WSDL, EJB
  implementations for the Web server
• WSRP (Web Services for Remote Portlets) an OASIS
  standard for integrating remote Web services into
  portals
• XML (Extensible Markup Language) a data markup
  language for Web services

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Conclusion

• Architecture plays a role in Enterprise IT
• EA is often used to align what IT does and plans
  to do with the business strategy
• There are frameworks that help how to think about
  the problem
• There are reference architectures to help how to
  create an approach
• There are architectural patterns to help in
  thinking how to build and deploy solutions
• There are architectural styles that can be
  applied in solution design