Service-oriented architecture - AbsoluteAstronomy.com

Software engineering

Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software...

, a Service-Oriented Architecture (SOA) is a set of principles and methodologies for designing and developing software in the form of interoperable

Interoperability

Interoperability is a property referring to the ability of diverse systems and organizations to work together . The term is often used in a technical systems engineering sense, or alternatively in a broad sense, taking into account social, political, and organizational factors that impact system to...

services. These services are well-defined business functionalities that are built as software components (discrete pieces of code

Subroutine

In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....

and/or data structure

Data structure

In computer science, a data structure is a particular way of storing and organizing data in a computer so that it can be used efficiently.Different kinds of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks...

s) that can be reused

Code reuse

Code reuse, also called software reuse, is the use of existing software, or software knowledge, to build new software.-Overview:Ad hoc code reuse has been practiced from the earliest days of programming. Programmers have always reused sections of code, templates, functions, and procedures...

for different purposes. SOA design

Systems design

Systems design is the process of defining the architecture, components, modules, interfaces, and data for a system to satisfy specified requirements. One could see it as the application of systems theory to product development...

principles are used during the phases of systems development and integration.

SOA also generally provides a way for consumers of services, such as web-based applications, to be aware of available SOA-based services. For example, several disparate departments within a company may develop and deploy SOA services in different implementation languages; their respective clients

Client (computing)

A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....

will benefit from a well-understood, well-defined interface to access them. XML

XML

Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

is often used for interfacing with SOA services, though this is not required. JSON

JSON

JSON , or JavaScript Object Notation, is a lightweight text-based open standard designed for human-readable data interchange. It is derived from the JavaScript scripting language for representing simple data structures and associative arrays, called objects...

is also becoming increasingly common.

SOA defines how to integrate widely disparate applications for a Web-based environment and uses multiple implementation platforms. Rather than defining an API, SOA defines the interface in terms of protocols and functionality. An endpoint is the entry point for such a SOA implementation.

Service orientation requires loose coupling
Loose coupling
In computing and systems design a loosely coupled system is one where each of its components has, or makes use of, little or no knowledge of the definitions of other separate components. The notion was introduced into organizational studies by Karl Weick...

of services with operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s, and other technologies that underlie applications. SOA separates functions into distinct units, or services, which developers make accessible over a network in order to allow users to combine and reuse them in the production of applications. These services and their corresponding consumers communicate with each other by passing data in a well-defined, shared format, or by coordinating an activity between two or more services.

SOA can be seen in a continuum

Continuum (theory)

Continuum theories or models explain variation as involving a gradual quantitative transition without abrupt changes or discontinuities. It can be contrasted with 'categorical' models which propose qualitatively different states.-In physics:...

, from older concepts of distributed computing

Distributed computing

Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...

and modular programming

Modular programming

Modular programming is a software design technique that increases the extent to which software is composed of separate, interchangeable components called modules by breaking down program functions into modules, each of which accomplishes one function and contains everything necessary to accomplish...

, through SOA, and on to current practices of mashup

Mashup (web application hybrid)

In Web development, a mashup is a Web page or application that uses and combines data, presentation or functionality from two or more sources to create new services...

s, SaaS

Saas

SAAS is an abbreviation for* Social Accountability Accreditation Services* Software as a service * Student Awards Agency for Scotland* Seattle Academy of Arts and Sciences* South Australian Ambulance Service...

, and Cloud Computing

Cloud computing

Cloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a utility over a network ....

(which some see as the offspring of SOA ).

Overview

The SOA implementations rely on a mesh of software services. Services comprise unassociated, loosely coupled units of functionality that have no call

Subroutine

In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....

s to each other embedded in them. Each service implements one action, such as filling out an online application for an account, or viewing an online bank statement, or placing an online booking or airline ticket order. Rather than services embedding calls to each other in their source code, they use defined protocols that describe how services pass

Message passing

Message passing in computer science is a form of communication used in parallel computing, object-oriented programming, and interprocess communication. In this model, processes or objects can send and receive messages to other processes...

and parse messages using description metadata.

SOA developers associate individual SOA objects by using orchestration

Orchestration (computers)

Orchestration describes the automated arrangement, coordination, and management of complex computer systems, middleware, and services.It is often discussed as having an inherent intelligence or even implicitly autonomic control, but those are largely aspirations or analogies rather than technical...

. In the process of orchestration the developer associates software functionality (the services) in a non-hierarchical arrangement using a software tool that contains a complete list of all available services, their characteristics, and the means to build an application utilizing these sources.

Underlying and enabling all of this requires metadata

Metadata

The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

in sufficient detail to describe not only the characteristics of these services, but also the data that drives them. Programmers have made extensive use of XML

XML

in SOA to structure data that they wrap in a nearly exhaustive description-container. Analogously, the Web Services Description Language

Web Services Description Language

The Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service provides a machine-readable description of how the service can be called, what parameters it expects and what data structures...

(WSDL) typically describes the services themselves, while the SOAP protocol describes the communications protocols. Whether these description languages are the best possible for the job, and whether they will become/remain the favorites in the future, remain open questions. SOA depends on data and services that are described by metadata that should meet the following two criteria:

The metadata should come in a form that software systems can use to configure dynamically by discovery and incorporation of defined services, and also to maintain coherence and integrity. For example, metadata could be used by other applications, like a catalogue, to perform autodiscovery of services without modifying the functional contract of a service.
The metadata should come in a form that system designers can understand and manage with a reasonable expenditure of cost and effort.

SOA aims to allow users to string together fairly large chunks of functionality to form ad hoc applications that are built almost entirely from existing software services. The larger the chunks, the fewer the interface points required to implement any given set of functionality; however, very large chunks of functionality may not prove sufficiently granular for easy reuse. Each interface brings with it some amount of processing overhead, so there is a performance consideration in choosing the granularity of services. The great promise of SOA suggests that the marginal cost

Marginal cost

In economics and finance, marginal cost is the change in total cost that arises when the quantity produced changes by one unit. That is, it is the cost of producing one more unit of a good...

of creating the n-th application is low, as all of the software required already exists to satisfy the requirements of other applications. Ideally, one requires only orchestration to produce a new application.

For this to operate, no interactions must exist between the chunks specified or within the chunks themselves. Instead, humans specify the interaction of services (all of them unassociated peers) in a relatively ad hoc way with the intent driven by newly emergent requirements. Thus the need for services as much larger units of functionality than traditional functions or classes, lest the sheer complexity of thousands of such granular objects overwhelm the application designer. Programmers develop the services themselves using traditional languages like Java

Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

, C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

, C++

C++

C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...

, C#, Visual Basic

Visual Basic

Visual Basic is the third-generation event-driven programming language and integrated development environment from Microsoft for its COM programming model...

, COBOL

COBOL

COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....

, or PHP

PHP

PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. For this purpose, PHP code is embedded into the HTML source document and interpreted by a web server with a PHP processor module, which generates the web page document...

.

SOA services feature loose coupling

Loose coupling

In computing and systems design a loosely coupled system is one where each of its components has, or makes use of, little or no knowledge of the definitions of other separate components. The notion was introduced into organizational studies by Karl Weick...

, in contrast to the functions that a linker binds together to form an executable

Executable

In computing, an executable file causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a data file that must be parsed by a program to be meaningful. These instructions are traditionally machine code instructions for a physical CPU...

, to a dynamically linked library or to an assembly. SOA services also run in "safe" wrappers (such as Java or .NET) and in other programming languages that manage memory allocation and reclamation, allow ad hoc and late binding, and provide some degree of indeterminate data typing.

, increasing numbers of third-party software companies offer software services for a fee. In the future, SOA systems may consist of such third-party services combined with others created in-house. This has the potential to spread costs over many customers and customer uses, and promotes standardization both in and across industries. In particular, the travel industry now has a well-defined and documented set of both services and data, sufficient to allow any reasonably competent software engineer to create travel-agency software using entirely off-the-shelf software services. Other industries, such as the finance industry, have also started making significant progress in this direction.

SOA as an architecture relies on service orientation as its fundamental design principle. If a service presents a simple interface that abstracts away its underlying complexity, users can access independent services without knowledge of the service's platform implementation.

Requirements

In order to efficiently use a SOA, the architecture must meet the following requirements:

Interoperability among different systems and programming languages that provides the basis for integration between applications on different platforms through a communication protocol. One example of such communication depends on the concept of messages
Message-oriented middleware
Message-oriented middleware is software or hardware infrastructure supporting sending and receiving messages between distributed systems. MOM allows application modules to be distributed over heterogeneous platforms and reduces the complexity of developing applications that span multiple...

. Using messages across defined message channels decreases the complexity of the end application, thereby allowing the developer of the application to focus on true application functionality instead of the intricate needs of a communication protocol.
Desire to create a federation of resources. Establish and maintain data flow to a federated database system
Federated database system
A federated database system is a type of meta-database management system , which transparently integrates multiple autonomous database systems into a single federated database. The constituent databases are interconnected via a computer network and may be geographically decentralized...

. This allows new functionality developed to reference a common business format for each data element.

Principles

The following guiding principles define the ground rules for development, maintenance, and usage of the SOA:

reuse, granularity
Granularity
Granularity is the extent to which a system is broken down into small parts, either the system itself or its description or observation. It is the "extent to which a larger entity is subdivided...

, modularity
Modularity (programming)
Modular programming is a software design technique that increases the extent to which software is composed of separate, interchangeable components called modules by breaking down program functions into modules, each of which accomplishes one function and contains everything necessary to accomplish...

, composability, componentization and interoperability
Interoperability
Interoperability is a property referring to the ability of diverse systems and organizations to work together . The term is often used in a technical systems engineering sense, or alternatively in a broad sense, taking into account social, political, and organizational factors that impact system to...

.
standards-compliance (both common and industry-specific).
services identification and categorization, provisioning and delivery, and monitoring and tracking.

The first published research of service orientation from an industry perspective was provided by Thomas Erl

Thomas Erl

Thomas Erl is a Canadian author, and public speaker known as a major contributor in the fields of service-oriented architecture, service-orientation and cloud computing.- Biography :...

of SOA Systems Inc. who defined eight specific service-orientation principles common to all primary SOA platforms. These principles were published in “Service-Oriented Architecture: Concepts, Technology, and Design”, on the www.soaprinciples.com research site, and in the September 2005 edition of the Web Services Journal (see Service-orientation

Service-orientation

Service-orientation is a design paradigm to build computer software in the form of services. Like other design paradigms , service-orientation provides a governing approach to automate business logic as distributed systems...

Standardized service contract – Services adhere to a communications agreement, as defined collectively by one or more service-description documents.

Service loose coupling
Service Loose Coupling
Within the service-orientation design paradigm, Service Loose Coupling is a design principle that is applied to the services in order to ensure that the service contract is not tightly coupled to the service consumers and to the underlying service logic and implementation...

– Services maintain a relationship that minimizes dependencies and only requires that they maintain an awareness of each other.

Service abstraction
Service Abstraction
Service Abstraction is a design principle that is applied within the service-orientation design paradigm so that the information published in a service contract is limited to what is required to effectively utilize the service i.e. the service contract should not contain any superfluous information...

– Beyond descriptions in the service contract, services hide logic from the outside world.

Service reusability
Service Reusability Principle
Service Reusability Principle is a design principle that is applied within the service-orientation design paradigm, in order to create services that have the potential to be reused across the enterprise...

– Logic is divided into services with the intention of promoting reuse.

Service autonomy
Service Autonomy Principle
Service Autonomy is a design principle that is applied within the service-orientation design paradigm, in order to services that have maximum control over their execution environment...

– Services have control over the logic they encapsulate.

Service granularity
Service Granularity Principle
Service Granularity is a design principle to provide optimal scope of the business functionality in a service operation. It is important to design the service operation with right granularity.- Interpretation :...

– A design consideration to provide optimal scope and right granular level of the business functionality in a service operation.

Service statelessness
Service Statelessness Principle
Service Statelessness is a design principle that is applied within the service-orientation design paradigm, in order to design scalable services by freeing up the services from managing their state data whenever possible...

- Services minimize resource consumption by deferring the management of state information when necessary

Service discoverability
Service discovery
Service discovery protocols are network protocols which allow automatic detection of devices and services offered by these devices on a computer network....

– Services are supplemented with communicative meta data by which they can be effectively discovered and interpreted.

Service composability
Service Composability Principle
Service Composability is a design principle, applied within the service-orientation design paradigm, which encourages the design of services in a manner so that they can be reused in multiple solutions that are themselves made up of composed services...

– Services are effective composition participants, regardless of the size and complexity of the composition.

Some authors also include the following principles:

Service normalization – Services are decomposed and/or consolidated to a level of normal form to minimize redundancy. In some cases, services are denormalized for specific purposes, such as performance optimization, access, and aggregation.
Service optimization – All else equal, high-quality services are generally preferable to low-quality ones.
Service relevance – Functionality is presented at a granularity recognized by the user as a meaningful service.
Service encapsulation – Many services are consolidated for use under the SOA. Often such services were not planned to be under SOA.
Service location transparency – This refers to the ability of a service consumer to invoke a service regardless of its actual location in the network. This also recognizes the discoverability property (one of the core principle of SOA) and the right of a consumer to access the service. Often, the idea of service virtualization also relates to location transparency. This is where the consumer simply calls a logical service while a suitable SOA-enabling runtime infrastructure component, commonly a service bus, maps this logical service call to a physical service.

The following references provide additional considerations for defining a SOA implementation:

SOA reference architecture provides a working design of an enterprise-wide SOA implementation with detailed architecture diagrams, component descriptions, detailed requirements, design pattern
Design pattern (computer science)
In software engineering, a design pattern is a general reusable solution to a commonly occurring problem within a given context in software design. A design pattern is not a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that...

s, opinions about standards, patterns on regulation compliance, standards templates etc.
Life-cycle management SOA Practitioners Guide Part 3: Introduction to Services Lifecycle introduces the services lifecycle and provides a detailed process for services management through the service lifecycle, from inception to retirement or repurposing of the services. It also contains an appendix that includes organization and governance best-practices, templates, comments on key SOA standards, and recommended links for more information.
SOA design principles provides more information about SOA realization using Service design principles

In addition, one might take the following factors into account when defining a SOA implementation:

Efficient use of system resources
Service maturity and performance
EAI (Enterprise Application Integration
Enterprise application integration
Enterprise Application Integration is defined as the use of software and computer systems architectural principles to integrate a set of enterprise computer applications.- Overview :...

)

Web services approach

Web service

A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...

s can implement a service-oriented architecture. Web services make functional building-blocks accessible over standard Internet protocols independent of platforms and programming languages. These services can represent either new applications or just wrappers around existing legacy systems to make them network-enabled.

Each SOA building block can play one or both of two roles:

Service provider - The service provider creates a web service
Web service
A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...

and possibly publishes its interface and access information to the service registry. Each provider must decide which services to expose, how to make trade-offs between security and easy availability, how to price the services, or (if no charges apply) how/whether to exploit them for other value. The provider also has to decide what category the service should be listed in for a given broker service and what sort of trading partner agreements are required to use the service. It registers what services are available within it, and lists all the potential service recipients. The implementer of the broker then decides the scope of the broker. Public brokers are available through the Internet, while private brokers are only accessible to a limited audience, for example, users of a company intranet. Furthermore, the amount of the offered information has to be decided. Some brokers specialize in many listings. Others offer high levels of trust in the listed services. Some cover a broad landscape of services and others focus within an industry. Some brokers catalog other brokers. Depending on the business model
Business model
A business model describes the rationale of how an organization creates, delivers, and captures value...

, brokers can attempt to maximize look-up requests, number of listings or accuracy of the listings. The Universal Description Discovery and Integration
Universal Description Discovery and Integration
Universal Description, Discovery and Integration is a platform-independent, Extensible Markup Language -based registry for businesses worldwide to list themselves on the Internet and a mechanism to register and locate web service applications...

(UDDI) specification defines a way to publish and discover information about Web services. Other service broker technologies include (for example) ebXML
EbXML
Electronic Business using eXtensible Markup Language, commonly known as e-business XML, or ebXML as it is typically referred to, is a family of XML based standards sponsored by OASIS and UN/CEFACT whose mission is to provide an open, XML-based infrastructure that enables the global use of...

(Electronic Business using eXtensible Markup Language) and those based on the ISO/IEC 11179
ISO/IEC 11179
ISO/IEC 11179 is an international standard for representing metadata for an organization in a metadata registry.- Intended purpose :...

Metadata Registry
Metadata registry
A metadata registry is a central location in an organization where metadata definitions are stored and maintained in a controlled method.-Use of Metadata Registries:...

(MDR) standard.
Service consumer - The service consumer or web service
Web service
A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...

client locates entries in the broker registry using various find operations and then binds to the service provider in order to invoke one of its web services. Whichever service the service-consumers need, they have to take it into the brokers, then bind it with respective service and then use it. They can access multiple services if the service provides multiple services.

SOA and web-service protocols

Implementors commonly build SOAs using web service

Web service

s standards (for example, SOAP) that have gained broad industry acceptance after recommendation of Version 1.2 from the W3C (World Wide Web Consortium) in 2003. These standards (also referred to as Web service specifications) also provide greater interoperability and some protection from lock-in to proprietary vendor software. One can, however, implement SOA using any service-based technology, such as Jini

Jini

Jini , also called Apache River, is a network architecture for the construction of distributed systems in the form of modular co-operating services.Originally developed by Sun, Jini was released under an open source license...

, CORBA

Çorba

Chorba , ciorbă , shurpa , shorpo , or sorpa is one of various kinds of soup or stew found in national cuisines across Middle East...

or REST

Representational State Transfer

Representational state transfer is a style of software architecture for distributed hypermedia systems such as the World Wide Web. The term representational state transfer was introduced and defined in 2000 by Roy Fielding in his doctoral dissertation...

Other SOA concepts

Architectures can operate independently of specific technologies. Designers can implement SOA using a wide range of technologies, including:

SOAP, RPC
Remote procedure call
In computer science, a remote procedure call is an inter-process communication that allows a computer program to cause a subroutine or procedure to execute in another address space without the programmer explicitly coding the details for this remote interaction...
REST
Rest
Rest may refer to:* Leisure* Human relaxation* SleepRest may also refer to:* Rest , a pause in a piece of music* Rest , the relation between two observers* Rest , a 2008 album by Gregor Samsa...
DCOM
Distributed component object model
Distributed Component Object Model is a proprietary Microsoft technology for communication among software components distributed across networked computers. DCOM, which originally was called "Network OLE", extends Microsoft's COM, and provides the communication substrate under Microsoft's COM+...
CORBA
Common Object Request Broker Architecture
The Common Object Request Broker Architecture is a standard defined by the Object Management Group that enables software components written in multiple computer languages and running on multiple computers to work together .- Overview:CORBA enables separate pieces of software written in different...
Web Services
DDS
Data Distribution Service
Data distribution service for real-time systems is a specification of a publish/subscribe middleware for distributed systems created by the Object Management Group in response to the need to standardize a data-centric publish-subscribe programming model for distributed systems.- History :A few...
WCF
Windows Communication Foundation
The Windows Communication Foundation , previously known as "Indigo", is an application programming interface in the .NET Framework for building connected, service-oriented applications.-The architectures:...

(Microsoft's implementation of web services now forms a part of WCF
Windows Communication Foundation
The Windows Communication Foundation , previously known as "Indigo", is an application programming interface in the .NET Framework for building connected, service-oriented applications.-The architectures:...

)

Implementations can use one or more of these protocols and, for example, might use a file-system mechanism to communicate data conforming to a defined interface specification between processes conforming to the SOA concept. The key is independent services with defined interfaces that can be called to perform their tasks in a standard way, without a service having foreknowledge of the calling application, and without the application having or needing knowledge of how the service actually performs its tasks.

Many implementers of SOA have begun to adopt an evolution of SOA concepts into a more advanced architecture called SOA 2.0

Event-driven SOA

Event-driven SOA is a form of service-oriented architecture , combining the intelligence and proactiveness of event-driven architecture with the organizational capabilities found in service offerings...

SOA enables the development of applications that are built by combining loosely coupled and interoperable services.

These services inter-operate based on a formal definition (or contract, e.g., WSDL

Web Services Description Language

) that is independent of the underlying platform and programming language. The interface definition hides the implementation

Information hiding

In computer science, information hiding is the principle of segregation of the design decisions in a computer program that are most likely to change, thus protecting other parts of the program from extensive modification if the design decision is changed...

of the language-specific service. SOA-based systems can therefore function independently of development technologies and platforms (such as Java, .NET, etc.). Services written in C# running on .NET platforms and services written in Java running on Java EE

Java Platform, Enterprise Edition

Java Platform, Enterprise Edition or Java EE is widely used platform for server programming in the Java programming language. The Java platform differs from the Java Standard Edition Platform in that it adds libraries which provide functionality to deploy fault-tolerant, distributed, multi-tier...

platforms, for example, can both be consumed by a common composite application (or client). Applications running on either platform can also consume services running on the other as web services that facilitate reuse. Managed environments can also wrap COBOL legacy systems and present them as software services. This has extended the useful life of many core legacy systems indefinitely, no matter what language they originally used.

SOA can support integration and consolidation activities within complex enterprise

Enterprise architecture

An enterprise architecture is a rigorous description of the structure of an enterprise, which comprises enterprise components , the externally visible properties of those components, and the relationships between them...

systems, but SOA does not specify or provide a methodology or framework

Conceptual framework

A conceptual framework is used in research to outline possible courses of action or to present a preferred approach to an idea or thought. For example, the philosopher Isaiah Berlin used the "hedgehogs" versus "foxes" approach; a "hedgehog" might approach the world in terms of a single organizing...

for documenting capabilities or services.

High-level language

High-level programming language

A high-level programming language is a programming language with strong abstraction from the details of the computer. In comparison to low-level programming languages, it may use natural language elements, be easier to use, or be from the specification of the program, making the process of...

s such as BPEL and specifications such as WS-CDL

WS-CDL

The Web Services Choreography Description Language is a W3C candidate recommendation. It is a language for describing how peer-to-peer participants collaborate...

and WS-Coordination

WS-Coordination

WS-Coordination is a Web Services specification developed by BEA Systems, IBM, and Microsoft and accepted by in its . It describes an extensible framework for providing protocols that coordinate the actions of distributed applications...

extend the service concept by providing a method of defining and supporting orchestration

Orchestration (computers)

of fine-grained services into more coarse-grained business services, which architects can in turn incorporate into workflows and business processes implemented in composite applications or portals

Enterprise portal

An enterprise portal, also known as an enterprise information portal or corporate portal, is a framework for integrating information, people and processes across organizational boundaries. It provides a secure unified access point, often in the form of a web-based user interface, and is designed...

.

researchers have started investigating the use of service component architecture

Service Component Architecture

Service Component Architecture is a software technology created by major software vendors including IBM and Oracle. SCA provides a model for composing applications that follow Service-Oriented Architecture principles...

(SCA) to implement SOA.

Service-oriented modeling

Service-oriented modeling

Service-oriented modeling is the discipline of modeling business and software systems, for the purpose of designing and specifying service-oriented business systems within a variety of architectural styles, such as enterprise architecture, application architecture, service-oriented architecture,...

is a SOA framework that identifies the various disciplines that guide SOA practitioners to conceptualize, analyze, design, and architect their service-oriented assets. The Service-oriented modeling framework (SOMF) offers a modeling language and a work structure or "map" depicting the various components that contribute to a successful service-oriented modeling approach. It illustrates the major elements that identify the “what to do” aspects of a service development scheme. The model enables practitioners to craft a project plan

Project plan

A project plan, according to the Project Management Body of Knowledge, isPRINCE2 defines:In some industries, particularly information technology, the term "project plan" can refer to a Gantt chart or other document that shows project activities along a timeline. While common, this use is inaccurate...

and to identify the milestones of a service-oriented initiative. SOMF also provides a common modeling notation to address alignment between business and IT organizations.

SOMF addresses the following principles:

business traceability
architectural best-practices traceability
Traceability
Traceability refers to the completeness of the information about every step in a process chain.The formal definition: Traceability is the ability to chronologically interrelate uniquely identifiable entities in a way that is verifiable....
technological traceability
SOA value proposition
Value proposition
A value proposition is a promise of value to be delivered and a belief from the customer of value that will be experienced. A value proposition can apply to an entire organization, or parts thereof, or customer accounts, or products or services....
software assets reuse
Asset reuse
The reuse of Intellectual Property assets is a strategy that many, in particular IT, companies are pursuing ,.The strategy for reusing non-IT related assets is called Asset recovery...
SOA integration strategies
technological abstraction and generalization
architectural components abstraction

SOA definitions

Commentators have provided multiple definitions of SOA.

The OASIS

OASIS (organization)

The Organization for the Advancement of Structured Information Standards is a global consortium that drives the development, convergence and adoption of e-business and web service standards...

group and the Open Group

The Open Group

The Open Group is a vendor and technology-neutral industry consortium, currently with over three hundred member organizations. It was formed in 1996 when X/Open merged with the Open Software Foundation...

have both created formal definitions. OASIS defines SOA

OASIS SOA Reference Model

The OASIS SOA Reference Model is a reference model for Service-oriented architecture produced by OASIS, an IT industry standards body. SOA is an architectural paradigm for matching needs and capabilities that may be under disparate domains of ownership...

as the following:

A paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations.
According to Thomas Erl

Thomas Erl

Thomas Erl is a Canadian author, and public speaker known as a major contributor in the fields of service-oriented architecture, service-orientation and cloud computing.- Biography :...

SOA represents an open, agile, extensible, federated, composable architecture autonomous, QoS-capable, vendor diverse, interoperable, discoverable, and potentially reusable services, implemented as Web services. SOA can establish an abstraction of business logic and technology, resulting in a loose coupling between these domains. SOA is an evolution of past platforms, preserving successful characteristics of traditional architectures, and bringing with it distinct principles that foster service-orientation in support of a service-oriented enterprise. SOA is ideally standardized throughout an enterprise, but achieving this state requires a planned transition and the support of a still evolving technology set.

Programmatic service contract

A service contract needs to have the following components:

Header
- Name – Name of the service. This should indicate in general terms what the service does, not just its definition
- Version – The version of this service contract
- Owner – The person/team in charge of the service
- Responsibility assignment (RACI)
  Responsibility assignment matrix
  A responsibility assignment matrix , also known as RACI matrix or Linear Responsibility Chart , describes the participation by various roles in completing tasks or deliverables for a project or business process...
  - Responsible – The role/person/team responsible for the deliverables of this contract/service. All versions of the contract
  - Accountable – Ultimate decision-maker in terms of this contract/service
  - Consulted – Whom one must consult before action is taken on this contract/service. This is two-way communication. These people have an impact on the decision or the execution of that decision.
  - Informed – Who must be informed that a decision or action is being taken. This is a one-way communication. These people are impacted by the decision or execution of that decision, but have no control over the action.
- Type – This is the type of the service: to help distinguish the layer in which it resides. Different implementations will have different service types. Examples of service types include:
  - Presentation
  - Process
  - Business
  - Data
  - Integration
Functional
- Functional requirement (from requirements document) – Indicates the functionality in specific bulleted items — what exactly this service accomplishes. The language should encourage test cases to prove the functionality is accomplished.
- Service operations – Methods, actions etc. Must be defined in terms of what part of the functionality it provides.
- Invocation – Indicates how to invoke the service. This includes the URL, interface, etc. There may be multiple invocation paths for the same service. One may have the same functionality for an internal and some external clients, each with different invocation means and interfaces. Examples:
  - SOAP
    SOAP
    SOAP, originally defined as Simple Object Access Protocol, is a protocol specification for exchanging structured information in the implementation of Web Services in computer networks...
  - REST
    Representational State Transfer
    Representational state transfer is a style of software architecture for distributed hypermedia systems such as the World Wide Web. The term representational state transfer was introduced and defined in 2000 by Roy Fielding in his doctoral dissertation...
  - Events triggers
Non-functional
- Security constraints – Defines who can execute this service in terms of roles or individual partners etc. and which invocation mechanism they can invoke.
- Quality of service – Determines the allowable failure rate
- Transactional – Is this capable of acting as part of a larger transaction and if so, how do we control that?
- Service level agreement – Determines the amount of latency the service is allowed to have to perform its actions
- Semantics – Dictates or defines the meaning of terms used in the description and interfaces of the service
- Process – Describes the process, if any, of the contracted service

SOA and network management architecture

the principles of SOA are being applied by network managers in their field. Examples of service-oriented network management architectures include TS 188 001 NGN Management OSS Architecture from ETSI and M.3060 Principles for the Management Of Next Generation Networks recommendation from the ITU-T

ITU-T

The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....

.

Tools for managing SOA infrastructure include:

HP Software & Solutions
HyPerformix IPS Performance Optimizer
HyPerformix
Hyperformix, Inc., based in Austin, Texas, United States is an enterprise software company that develops solutions designed to deliver business insight into IT operations. Hyperformix has trademarked Predictive IT Management, a combination of modeling technology and best practice methodology...
IBM Tivoli Framework
IBM Tivoli Framework
IBM Tivoli Management Framework is a systems management platform from IBM...
Red Hat JBoss Operations Network
JBoss operations network
JBoss Operations Network is free software/open-source Java EE-based network management software. JBoss Operations Network is part of the JBoss Enterprise Middleware portfolio of software. JBoss ON is an administration and management platform for the development, testing, deployment, and monitoring...
Oracle SOA Management Pack Enterprise Edition (Official Product Page)

Benefits

Some enterprise architect

Enterprise architect

Enterprise architects are practitioners of enterprise architecture; an information technology management discipline that operates within organizations.-Role of enterprise architects:...

s believe that SOA can help businesses respond more quickly and more cost-effectively to changing market conditions. This style of architecture promotes reuse at the macro (service) level rather than micro (classes) level. It can also simplify interconnection to – and usage of – existing IT (legacy) assets.

In some respects, one can regard SOA as an architectural evolution rather than as a revolution. It captures many of the best practice

Best practice

A best practice is a method or technique that has consistently shown results superior to those achieved with other means, and that is used as a benchmark...

s of previous software architectures. In communications systems, for example, little development of solutions that use truly static bindings to talk to other equipment in the network has taken place. By formally embracing a SOA approach, such systems can position themselves to stress the importance of well-defined, highly inter-operable interfaces.

Some have questioned whether SOA simply revives concepts like modular programming (1970s), event-oriented design (1980s) or interface/component-based design (1990s). SOA promotes the goal of separating users (consumers) from the service implementations. Services can therefore be run on various distributed platforms and be accessed across networks. This can also maximize reuse of services.

SOA realizes its business and IT benefits by utilizing an analysis and design methodology when creating services. This methodology ensures that services remain consistent with the architectural vision and roadmap and that they adhere to principles of service-orientation. Arguments supporting the business and management aspects from SOA are outlined in various publications.

A service comprises a stand-alone unit of functionality available only via a formally defined interface. Services can be some kind of "nano-enterprises" that are easy to produce and improve. Also services can be "mega-corporations" constructed as the coordinated work of subordinate services.

Services generally adhere to the following principles of service-orientation:

abstraction
autonomy
composability
discoverability
formal contract
loose coupling
reusability
statelessness

A mature rollout of SOA effectively defines the API of an organization.

Reasons for treating the implementation of services as separate projects from larger projects include:

Separation promotes the concept to the business that services can be delivered quickly and independently from the larger and slower-moving projects common in the organization. The business starts understanding systems and simplified user interfaces calling on services. This advocates agility
Agility
* Agility is a physical trait of an animal or person, and a component of physical fitness. It is the ability to change the body's position and direction with speed and precision.Agility may also refer to:In Sport:...

. That is to say, it fosters business innovations and speeds up time-to-market.
Separation promotes the decoupling of services from consuming projects. This encourages good design insofar as the service is designed without knowing who its consumers are.
Documentation and test artifacts of the service are not embedded within the detail of the larger project. This is important when the service needs to be reused later.

An indirect benefit of SOA involves dramatically simplified testing. Services are autonomous, stateless, with fully documented interfaces, and separate from the cross-cutting concerns of the implementation.

If an organization possesses appropriately defined test data, then a corresponding stub is built that reacts to the test data when a service is being built. A full set of regression tests, scripts, data, and responses is also captured for the service. The service can be tested as a 'black box' using existing stubs corresponding to the services it calls. Test environments can be constructed where the primitive and out-of-scope services are stubs, while the remainder of the mesh is test deployments of full services. As each interface is fully documented with its own full set of regression test documentation, it becomes simple to identify problems in test services. Testing evolves to merely validate that the test service operates according to its documentation, and finds gaps in documentation and test cases of all services within the environment. Managing the data state of idempotent services is the only complexity.

Examples may prove useful to aid in documenting a service to the level where it becomes useful. The documentation of some APIs within the Java Community Process provide good examples. As these are exhaustive, staff would typically use only important subsets. The 'ossjsa.pdf' file within JSR-89 exemplifies such a file.

Challenges in adopting SOA

One obvious and common challenge faced involves managing services metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

. SOA-based environments can include many services that exchange messages to perform tasks. Depending on the design, a single application may generate millions of messages. Managing and providing information on how services interact can become complex. This becomes even more complicated when these services are delivered by different organizations within the company or even different companies (partners, suppliers, etc.). This creates huge trust issues across teams; hence SOA Governance comes into the picture.

Another challenge involves the lack of testing in SOA space. There are no sophisticated tools that provide testability of all headless services (including message and database services along with web services) in a typical architecture. Lack of horizontal trust requires that both producers and consumers test services on a continuous basis. SOA's main goal is to deliver agility to businesses. Therefore it is important to invest in a testing framework (build it or buy it) that would provide the visibility required to find the culprit in the architecture. Business agility

Business agility

Business agility is the ability of a business to adapt rapidly and cost efficiently in response to changes in the business environment. Business agility can be maintained by maintaining and adapting goods and services to meet customer demands, adjusting to the changes in a business environment and...

requires SOA services to be controlled by the business goals and directives as defined in the business Motivation Model

Business Motivation Model

The Business Motivation Model in enterprise architecture provides a scheme and structure for developing, communicating, and managing business plans in an organized manner...

(BMM).

Another challenge relates to providing appropriate levels of security. Security models built into an application may no longer suffice when an application exposes its capabilities as services that can be used by other applications. That is, application-managed security is not the right model for securing services. A number of new technologies and standards have started to emerge and provide more appropriate models for security in SOA

SOA Security

Service-oriented architecture allows different ways to develop applications by combining services. The main premise of SOA is to erase application boundaries and technology differences. As applications are opened up, how we can combine these services securely becomes an issue...

.

Finally, the impact of changing a service that touches multiple business domains will require a higher level of change management governance

As SOA and the WS-* specifications practitioners expand, update and refine their output, they encounter a shortage of skilled people to work on SOA-based systems, including the integration of services and construction of services infrastructure.

Interoperability becomes an important aspect of SOA implementations. The WS-I organization has developed basic profile (BP) and basic security profile (BSP) to enforce compatibility. WS-I has designed testing tools to help assess whether web services conform to WS-I profile guidelines. Additionally, another charter has been established to work on the Reliable Secure Profile.

Significant vendor hype surrounds SOA, which can create exaggerated expectations. Product stacks continue to evolve as early adopters test the development and runtime products with real-world problems. SOA does not guarantee reduced IT costs, improved systems agility or shorter time to market. Successful SOA implementations may realize some or all of these benefits depending on the quality and relevance of the system architecture and design.

Internal IT delivery organizations routinely initiate SOA efforts, and some do a poor job of introducing SOA concepts to a business with the result that SOA remains misunderstood within that business. The adoption of SOA starts to meet IT delivery needs instead of those of the business, resulting in an organization with, for example, superlative laptop provisioning services, instead of one that can quickly respond to market opportunities. Business leadership

Leadership

Leadership has been described as the “process of social influence in which one person can enlist the aid and support of others in the accomplishment of a common task". Other in-depth definitions of leadership have also emerged.-Theories:...

also frequently becomes convinced that the organization is executing well on SOA.

One of the most important benefits of SOA is its ease of reuse. Therefore accountability and funding models must ultimately evolve within the organization. A business unit needs to be encouraged to create services that other units will use. Conversely, units must be encouraged to reuse services. This requires a few new governance components:

Each business unit creating services must have an appropriate support structure in place to deliver on its service-level
Service level
Service level measures the performance of a system. Certain goals are defined and the service level gives the percentage to which they should be achieved...

obligations, and to support enhancing existing services strictly for the benefit of others. This is typically quite foreign to business leader
Leader
A leader is one who influences or leads others.Leader may also refer to:- Newspapers :* Leading article, a piece of writing intended to promote an opinion, also called an editorial* The Leader , published 1909–1967...

s.
Each business unit consuming services accepts the apparent risk of reusing services outside their own control, with the attendant external project dependencies, etc.
An innovative funding model is needed as incentive to drive these behaviors above. Business units normally pay the IT organization to assist during projects and then to operate the environment. Corporate incentives should discount these costs to service providers and create internal revenue streams from consuming business units to the service provider. These streams should be less than the costs of a consumer simply building it the old-fashioned way. This is where SOA deployments can benefit from the SaaS
Software as a Service
Software as a service , sometimes referred to as "on-demand software," is a software delivery model in which software and its associated data are hosted centrally and are typically accessed by users using a thin client, normally using a web browser over the Internet.SaaS has become a common...

monetization architecture.

Criticisms of SOA

Some criticisms of SOA depend on conflating SOA with Web services. For example, some critics claim SOA results in the addition of XML layers, introducing XML parsing and composition. In the absence of native or binary forms of remote procedure call

Remote procedure call

In computer science, a remote procedure call is an inter-process communication that allows a computer program to cause a subroutine or procedure to execute in another address space without the programmer explicitly coding the details for this remote interaction...

(RPC), applications could run slower and require more processing power, increasing costs. Most implementations do incur these overheads, but SOA can be implemented using technologies (for example, Java Business Integration

Java Business Integration

Java Business Integration is a specification developed under the Java Community Process for an approach to implementing a service-oriented architecture . The JCP reference is JSR 208 for JBI 1.0 and JSR 312 for JBI 2.0....

(JBI) and data distribution service

Data Distribution Service

Data distribution service for real-time systems is a specification of a publish/subscribe middleware for distributed systems created by the Object Management Group in response to the need to standardize a data-centric publish-subscribe programming model for distributed systems.- History :A few...

(DDS)) that do not depend on remote procedure calls or translation through XML. At the same time, emerging open-source XML parsing technologies (such as VTD-XML

VTD-XML

Virtual Token Descriptor for eXtensible Markup Language refers to a collection of cross-platform XML processing technologies centered around a non-extractive XML, "document-centric" parsing technique called Virtual Token Descriptor...

) and various XML-compatible binary formats promise to significantly improve SOA performance.

Stateful services require both the consumer and the provider to share the same consumer-specific context, which is either included in or referenced by messages exchanged between the provider and the consumer. This constraint has the drawback that it could reduce the overall scalability of the service provider if the service-provider needs to retain the shared context for each consumer. It also increases the coupling between a service provider and a consumer and makes switching service providers more difficult. Ultimately, some critics feel that SOA services are still too constrained by applications they represent.

Another concern relates to the ongoing evolution of WS-* standards and products (e. g., transaction, security), and SOA can thus introduce new risks unless properly managed and estimated with additional budget and contingency for additional proof-of-concept work.

Some critics regard SOA as merely an obvious evolution of well-deployed architectures (open interfaces, etc.).

IT system designs sometimes overlook the desirability of modifying systems readily. Many systems, including SOA-based systems, hard-code the operations, goods and services of the organization, thus restricting their online service and business agility in the global marketplace.

The next step in the design process covers the definition of a service delivery platform (SDP) and its implementation. In the SDP design phase one defines the business information models, identity management, products, content, devices, and the end-user service characteristics, as well as how agile the system is so that it can deal with the evolution of the business and its customers.

SOA Manifesto

In October 2009, at the 2nd International SOA Symposium, a mixed group of 17 independent SOA practitioners and vendors, the "SOA Manifesto Working Group", announced the publication of the SOA Manifesto. The SOA Manifesto is a set of objectives and guiding principles that aim to provide a clear understanding and vision of SOA and service-orientation.
Its purpose is rescuing the SOA concept from an excessive use of the term by the vendor community and "a seemingly endless proliferation of misinformation and confusion". http://www.soa-manifesto.org/aboutmanifesto.html

The manifesto provides a broad definition of SOA, the values it represents for the signatories and some guiding principles. The manifesto prioritizes:

Business value over technical strategy
Strategic goals over project-specific benefits
Intrinsic interoperability over custom integration
Shared services over specific-purpose implementations
Flexibility over optimization
Evolutionary refinement over pursuit of initial perfection

As of September 2010, the SOA Manifesto had been signed by more than 700 signatories and had been translated to nine languages.

Roadmap

The roadmap to SOA involves:

Understanding the industry specific end state for the first iteration
Gather the current state of business process maintenance, applications, integrations, security, master data and governance
Reducing the SOA readiness gap between various entities

The various entities would be in one of the SOA readiness states.

Business process maintenance

Ad-hoc: processes are defined as and when needed
Documented: business steps are documented in disparate documents
Structured: process management tools used albeit disconnected
Services: processes designed as services through standardized process management tool

Integration

Point to point: applications directly interface with required parties
Loosely coupled: some applications use an intermediary that abstracts the interface
Static services: services available but bound to other Static Applications
Dynamic binding: static services bound in a dynamic way through Pub-Sub
Publish/subscribe
Publish–subscribe is a messaging pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers. Published messages are characterized into classes, without knowledge of what, if any, subscribers there may be...
Dynamic services: services that can dynamically sense when they are required and respond

appropriately.

Applications

Standalone: applications requiring large interface efforts
Service-wrapped: application(s) wrapped as a service
Exposed APIs: applications have service based API's
Exposed services: this makes the applications reusable
Dynamic discovery: applications can be discovered by other applications

Security

Application level authentication and authorization: every application is accessed in its own silo
Loose authentication control: some applications are on LDAP
Tight directory-controlled authentication: SSO
SSO
SSO may refer to:*Statistical Society of Ottawa, the Ottawa Regional Association of the Statistical Society of Canada and the Ottawa Chapter of the American Statistical Association.*Sanitary sewer overflow...

-enabled across most applications
Centrally controlled identity and access management

Master data

Application-controlled: all applications control their master data
Partial sharing: some applications share master data but not all masterdata
Centralized master-data maintenance: most master data is shared and maintained through some MDM implementation

SOA, Web 2.0, services over the messenger, and mashups

Web 2.0

The term Web 2.0 is associated with web applications that facilitate participatory information sharing, interoperability, user-centered design, and collaboration on the World Wide Web...

, a perceived "second generation" of web activity, primarily features the ability of visitors to contribute information for collaboration and sharing. Web 2.0 applications often use REST

Rest

Rest may refer to:* Leisure* Human relaxation* SleepRest may also refer to:* Rest , a pause in a piece of music* Rest , the relation between two observers* Rest , a 2008 album by Gregor Samsa...

-ful web services and commonly feature AJAX

Ajax (programming)

Ajax is a group of interrelated web development methods used on the client-side to create asynchronous web applications...

based user interfaces, utilizing web syndication

Web syndication

Web syndication is a form of syndication in which website material is made available to multiple other sites. Most commonly, web syndication refers to making web feeds available from a site in order to provide other people with a summary or update of the website's recently added content...

, blogs, and wikis. While there are no set standards for Web 2.0, it is characterized by building on the existing Web server architecture and using services. Web 2.0 can therefore be regarded as displaying some SOA characteristics.

Some commentators also regard mashup

Mashup (web application hybrid)

In Web development, a mashup is a Web page or application that uses and combines data, presentation or functionality from two or more sources to create new services...

s as Web 2.0 applications. The term "Business Mashups" has been coined to describe web applications that combine content from more than one source into an integrated user experience

User experience

User experience is the way a person feels about using a product, system or service. User experience highlights the experiential, affective, meaningful and valuable aspects of human-computer interaction and product ownership, but it also includes a person’s perceptions of the practical aspects such...

that shares many of the characteristics of service-oriented business applications (SOBAs). SOBAs are applications composed of services in a declarative manner. There is ongoing debate about "the collision of Web 2.0, mashups, and SOA," with some stating that Web 2.0 applications are a realization of SOA composite and business applications.

Web 2.0

Tim O'Reilly

Tim O'Reilly is the founder of O'Reilly Media and a supporter of the free software and open source movements.-Life and career:...

coined the term "Web 2.0

Web 2.0

The term Web 2.0 is associated with web applications that facilitate participatory information sharing, interoperability, user-centered design, and collaboration on the World Wide Web...

" to describe a perceived, quickly-growing set of web-based applications. A topic that has experienced extensive coverage involves the relationship between Web 2.0 and Service-Oriented Architectures (SOAs). SOA is considered as the philosophy of encapsulating application logic in services with a uniformly defined interface and making these publicly available via discovery mechanisms. The notion of complexity-hiding and reuse, but also the concept of loosely coupling services has inspired researchers to elaborate on similarities between the two philosophies, SOA and Web 2.0, and their respective applications. Some argue Web 2.0 and SOA have significantly different elements and thus can not be regarded “parallel philosophies”, whereas others consider the two concepts as complementary and regard Web 2.0 as the global SOA.

The philosophies of Web 2.0 and SOA serve different user needs and thus expose differences with respect to the design and also the technologies used in real-world applications. However, , use-cases demonstrated the potential of combining technologies and principles of both Web 2.0 and SOA.

In an "Internet of Services

Internet of Services

or Internet of Services isextending today’s Internet to become service-enabled. The Internet of Services is not an overhaul of the Internet but, for the most part, an application of it, where classical barriers and inefficiencies are removed from service access.-Situation:Over the last decade, the...

", all people, machines, and goods will have access via the network infrastructure of tomorrow. The Internet will thus offer services for all areas of life

Personal life

Personal life is the course of an individual's life, especially when viewed as the sum of personal choices contributing to one's personal identity. It is a common notion in modern existence—although more so in more prosperous parts of the world such as Western Europe and North America...

and business, such as virtual insurance, online banking and music, and so on. Those services will require a complex services infrastructure including service-delivery platforms bringing together demand and supply. Building blocks for the Internet of Services include SOA, Web 2.0 and semantics on the technology side; as well as novel business models, and approaches to systematic and community-based innovation.

Even though Oracle indicates that Gartner

Gartner

Gartner, Inc. is an information technology research and advisory firm headquartered in Stamford, Connecticut, United States. It was known as GartnerGroup until 2001....

is coining a new term, Gartner analysts indicate that they call this advanced SOA and refer to it as "SOA 2.0"

Event-driven SOA

. Most of the major middleware

Middleware

Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...

vendors (e. g., Red Hat

Red Hat

Red Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....

, webMethods

WebMethods

webMethods is an enterprise software company, acquired by Software AG, focused on application integration, business process integration and B2B partner integration. Founded in 1996, the company pioneered the use of web services to connect software applications together within a single organization...

, TIBCO Software

TIBCO Software

TIBCO Software Inc. is a provider of infrastructure software for companies to use on-premise or as part of cloud computing environments. TIBCO manages information, decisions, processes and applications in real-time for over 4,000 customers worldwide...

, IBM

IBM

International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

, Sun Microsystems

Sun Microsystems

Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

, and Oracle

Oracle Corporation

Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

) have had some form of SOA 2.0 attributes for years.

Digital nervous system

SOA implementations have been described as representing a piece of the larger vision known as the digital nervous system

Digital Nervous System

Digital nervous system is a phrase, popularly associated with Bill Gates of Microsoft, used to describe a vision for how the IT infrastructure of an enterprise could be analogous to the autonomic nervous system of a biological organism. Gates made extensive use of the term in his 1999 book ...

or the Zero Latency Enterprise.

External links

InfoWorld
InfoWorld
InfoWorld is an information technology online media and events business operating under the umbrella of InfoWorld Media Group, a division of IDG...

magazine provides a 3-minute video explaining SOA and how it works
Recommendations for beginning an SOA initiative by Ian Robinson (video)
The pros and cons of using SOAP/WSDL/WS-* and REST for SOA by Mark Little (video)
Technology choices and business ramifications around implementing an SOA, an interview with Ian Robinson (video)
Service-oriented architecture's 6 burning questions

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Overview

Requirements

Principles

Web services approach

SOA and web-service protocols

Other SOA concepts

SOA definitions

Programmatic service contract

SOA and network management architecture

Benefits

Challenges in adopting SOA

Criticisms of SOA

SOA Manifesto

Roadmap

Business process maintenance

Integration

Applications

Security

Master data

SOA, Web 2.0, services over the messenger, and mashups

Web 2.0

Digital nervous system

See also

External links