Enterprise architecture

An enterprise architecture (EA) is a rigorous description of the structure of an enterprise, its decomposition into subsystems, the relationships between the subsystems, the relationships with the external environment, the terminology to use, and the guiding principles for the design and evolution of an enterprise . This description is comprehensive, including enterprise goals, business functions, business process, roles, organisational structures, business information, software applications and computer systems.

Practitioners of EA call themselves "enterprise architects." An enterprise architect is a person responsible for developing the enterprise architecture and is often called upon to draw conclusions from it. By producing an enterprise architecture, architects are providing a tool for identifying opportunities to improve the enterprise, in a manner that more effectively and efficiently pursues its purpose.

The scope of an enterprise architecture

The term enterprise refers to a complex, socio-technical system that comprises interdependent resources of people, information, and technology that must interact with each other and their environment in support of a common mission .

The term "enterprise" is used because it is generally applicable in many circumstances, including

• Public or private sector organizations
• An entire business or corporation
• A part of a larger enterprise (such as a business unit),
• A conglomerate of several organisations, such as a joint venture or partnership
• A multiply-outsourced business operation.

Defining the boundary or scope of the enterprise to be described is an important first step in creating the enterprise architecture. It should also be noted that the term "enterprise" as used in enterprise architecture generally means more than the information systems employed by an organization.

Methods and frameworks

Enterprise architects use various business methods, analytical techniques and conceptual tools to understand and document the structure and dynamics of an enterprise. In doing so, they produce lists, drawings, documents and models, together called "artifacts". These artifacts describe the logical organization of business functions, business capabilities, business processes, people, information resources, business systems, software applications, computing capabilities, information exchange and communications infrastructure within the enterprise.

A collection of these artifacts, sufficiently complete to describe the enterprise in useful ways, is considered by EA practitioners an ‘enterprise’ level architectural description, or enterprise architecture, for short. The UK National Computing Centre EA best practice guidance states

Normally an EA takes the form of a comprehensive set of cohesive models that describe the structure and functions of an enterprise.

and continues

The individual models in an EA are arranged in a logical manner that provides an ever-increasing level of detail about the enterprise: its objectives and goals; its processes and organisation; its systems and data; the technology used and any other relevant spheres of interest.

This is the definition of enterprise architecture implicit in several EA frameworks including the popular TOGAF architectural framework.

An enterprise architecture framework collects together tools, techniques, artifact descriptions, process models, reference models and guidance used by architects in the production of enterprise-specific architectural description.

See the related article on enterprise architecture frameworks for further information.

In 1992, Steven Spewak described a process for creating an enterprise architecture that is widely used in educational courses.

Areas of practice

Several enterprise architecture frameworks break down the practice of enterprise architecture into a number of practice areas or "domains". In his book on Enterprise Architecture, Spewak divides the practice into two domains at 'level 2': "Business Modelling" and "Current Systems and Technology" and three subordinate domains at 'level 3': "Data Architecture", "Applications Architecture" and "Technology Architecture". The final level of Spewak's EAP is the "Implementation" or "Methods" level, which deals with "how" to migrate the Enterprise to match the new model.

The popular TOGAF framework divides the practice into three domains: "Business Architecture", "Information Systems Architecture" and "Technology Architecture" and then subdivides the information systems architecture into "Information Architecture and "Applications Architecture".

The Strategic Architecture Model allows for a flexible division into up to ten domains covering many aspects of an enterprise from its objectives and goals through its projects and programmes to its software applications and technology.

The dividing of the practice into a number of domains allows enterprise architects to describe an enterprise from a number of important perspectives. This practice also encourages the contributions of many individuals and allows the practice as a whole to make good use of individual domain-specific expertise and knowledge. By taking this approach, enterprise architects can ensure a holistic description is produced.

The popular and most common four domains and their component parts look like this:

1. Business:
   1. Strategy maps, goals, corporate policies, Operating Model
   2. Functional decompositions (e.g. IDEF0, SADT), business capabilities and organizational models expressed as enterprise / line of business business architecture
   3. Business processes, Workflow and Rules that articulate the assigned authorities, responsibilities and policies
   4. Organization cycles, periods and timing
   5. Suppliers of hardware, software, and services
2. Information:
   1. Information architecture - a holistic view on the flow of information in an enterprise
   2. Metadata - data that describes your enterprise data elements
   3. Data models: conceptual expressed as enterprise information architectures, logical, and physical
3. Applications:
   1. Application software inventories and diagrams, expressed as conceptual / functional or system enterprise / line of business architectures
   2. Interfaces between applications - that is: events, messages and data flows
4. Technology:
   1. Inter-application mediating software or 'middleware'.
   2. Application execution environments and operating frameworks including applications server environments and operating systems, authentication and authorisation environments, security systems and operating and monitoring systems.
   3. Hardware, platforms, and hosting: servers, datacentres and computer rooms
   4. Local and wide area networks, Internet connectivity diagrams
   5. Intranet, Extranet, Internet, eCommerce, EDI links with parties within and outside of the organization
   6. Operating System
   7. Infrastructure software: Application servers, DBMS
   8. Programming Languages, etc. expressed as enterprise / line of business technology architecture.

Using an enterprise architecture

Describing the architecture of an enterprise aims primarily to improve the effectiveness or efficiency of the business itself. This includes innovations in the structure of an organization, the centralization or federation of business processes, the quality and timeliness of business information, or ensuring that money spent on information technology (IT) can be justified.

One method of using this information to improve the functioning of a business, as described in the TOGAF architectural framework, involves developing an "architectural vision": a description of the business that represents a “target” or “future state” goal. Once this vision is well understood, a set of intermediate steps are created that illustrate the process of changing from the present situation to the target. These intermediate steps are called “transitional architectures” by TOGAF. Similar methods have been described in other enterprise architecture frameworks.

The growing use of enterprise architecture

Documenting the architecture of enterprises is becoming a common practice within the U.S. Federal Government in the context of the Capital Planning and Investment Control (CPIC) process. The Federal Enterprise Architecture (FEA) reference models serve as a framework to guide Federal agencies in the development of their architectures. Companies such as Independence Blue Cross, Intel, Volkswagen AG and InterContinental Hotels Group have also applied enterprise architecture to improve their business architectures as well as to improve business performance and productivity.

Relationship to other disciplines

Enterprise architecture has become a key component of the information technology governance process in many organizations. These companies have implemented a formal enterprise architecture process as part of their IT management strategy. While this may imply that enterprise architecture is closely tied to IT, it should be viewed in the broader context of business optimization in that it addresses business architecture, performance management and process architecture as well as more technical subjects. Depending on the organization, enterprise architecture teams may also be responsible for some aspects of performance engineering, IT portfolio management and metadata management.

The following image from the 2006 FEA Practice Guidance of US OMB sheds light on the relationship between enterprise architecture and segment(BPR) or Solution architectures. (From this figure and a bit of thinking one can see that software architecture is truly a solution architecture discipline, for example.)

Activities such as software architecture, network architecture, database architecture may be seen as partial contributions to a solution architecture.

Published examples of enterprise architecture

It is uncommon for a commercial organization to publish rich detail from their enterprise architecture descriptions. Doing so can provide competitors information on weaknesses and organizational flaws that could hinder the company's market position. However, many government agencies around the world have begun to publish the architectural descriptions that they have developed. Good examples include the US Department of the Interior, and the US Department of Defense business transformation agency.

See also

• Enterprise Architect
• Enterprise Architecture framework
• Enterprise Architecture Planning
• Enterprise engineering
• Enterprise Life Cycle
• Enterprise Unified Process
• GINA : Global Information Network Architecture
• IT Governance
• IT Portfolio Management
• IT Service Management
• Enterprise Architecture Assessment Framework