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Enterprise Architecture - TOGAF and ArchiMate

TOGAF is an architecture framework - The Open Group Architecture Framework. TOGAF provides the methods and tools for assisting in the acceptance, production, use, and maintenance of an enterprise architecture. It is based on an iterative process model supported by best practices and a re-usable set of existing architecture assets.

ArchiMate, an Open Group Standard, is an open and independent modelling language for enterprise architecture, supported by different tool vendors and consulting firms.

Architecture in the Context of TOGAF

ISO/IEC 42010:2007 defines "architecture" as:

"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."

Enterprise Architecture Scope and Techniquies

TOGAF embraces but does not strictly adhere to ISO/IEC 42010:2007 terminology. In TOGAF, "architecture" has two meanings depending upon the context:

A formal description of a system, or a detailed plan of the system at component level to guide its implementation
The structure of components, their inter-relationships, and the principles and guidelines governing their design and evolution over time

In TOGAF we endeavor to strike a balance between promoting the concepts and terminology of ISO/IEC 42010:2007 - ensuring that our usage of terms defined by ISO/IEC 42010:2007 is consistent with the standard - and retaining other commonly accepted terminology that is familiar to the majority of the TOGAF readership. For more on terminology, refer to Definitions and Part IV, Architectural Artifacts .

What Kind of Architecture Does TOGAF Deal With?

There are four architecture domains that are commonly accepted as subsets of an overall enterprise architecture, all of which TOGAF is designed to support:

	The Business Architecture defines the business strategy, governance, organization, and key business processes.
	The Data Architecture describes the structure of an organization's logical and physical data assets and data management resources.
	The Application Architecture provides a blueprint for the individual application systems to be deployed, their interactions, and their relationships to the core business processes of the organization.
	The Technology Architecture describes the logical software and hardware capabilities that are required to support the deployment of business, data, and application services. This includes IT infrastructure, middleware, networks, communications, processing, standards, etc.

Architecture Development Method

The TOGAF Architecture Development Method (ADM) provides a tested and repeatable process for developing architectures. The ADM includes establishing an architecture framework, developing architecture content, transitioning, and governing the realization of architectures.

All of these activities are carried out within an iterative cycle of continuous architecture definition and realization that allows organizations to transform their enterprises in a controlled manner in response to business goals and opportunities.

Phases within the ADM are as follows:

	The Preliminary Phase describes the preparation and initiation activities required to prepare to meet the business directive for a new enterprise architecture, including the definition of an Organization-Specific Architecture framework and the definition of principles.
	Phase A: Architecture Vision describes the initial phase of an architecture development cycle. It includes information about defining the scope, identifying the stakeholders, creating the Architecture Vision, and obtaining approvals.
	Phase B: Business Architecture describes the development of a Business Architecture to support an agreed Architecture Vision.
	Phase C: Information Systems Architectures describes the development of Information Systems Architectures for an architecture project, including the development of Data and Application Architectures.
	Phase D: Technology Architecture describes the development of the Technology Architecture for an architecture project.
	Phase E: Opportunities & Solutions conducts initial implementation planning and the identification of delivery vehicles for the architecture defined in the previous phases.
	Phase F: Migration Planning addresses the formulation of a set of detailed sequence of transition architectures with a supporting Implementation and Migration Plan.
	Phase G: Implementation Governance provides an architectural oversight of the implementation.
	Phase H: Architecture Change Management establishes procedures for managing change to the new architecture.
	Requirements Management examines the process of managing architecture requirements throughout the ADM.

Deliverables, Artifacts, and Building Blocks

Architects executing the ADM will produce a number of outputs as a result of their efforts, such as process flows, architectural requirements, project plans, project compliance assessments, etc. The TOGAF Architecture Content Framework (see Part IV, Introduction) provides a structural model for architectural content that allows major work products to be consistently defined, structured, and presented.

The Architecture Content Framework uses the following three categories to describe the type of architectural work product within the context of use:

A deliverable is a work product that is contractually specified and in turn formally reviewed, agreed, and signed off by the stakeholders. Deliverables represent the output of projects and those deliverables that are in documentation form will typically be archived at completion of a project, or transitioned into an Architecture Repository as a reference model, standard, or snapshot of the Architecture Landscape at a point in time.

An artifact is a more granular architectural work product that describes an architecture from a specific viewpoint. Examples include a network diagram, a server specification, a use-case specification, a list of architectural requirements, and a business interaction matrix. Artifacts are generally classified as catalogs (lists of things), matrices (showing relationships between things), and diagrams (pictures of things). An architectural deliverable may contain many artifacts and artifacts will form the content of the Architecture Repository.

A building block represents a (potentially re-usable) component of business, IT, or architectural capability that can be combined with other building blocks to deliver architectures and solutions.

Building blocks can be defined at various levels of detail, depending on what stage of architecture development has been reached. For instance, at an early stage, a building block can simply consist of a name or an outline description. Later on, a building block may be decomposed into multiple supporting building blocks and may be accompanied by a full specification. Building blocks can relate to "architectures" or "solutions".

Architecture Building Blocks (ABBs) typically describe required capability and shape the specification of Solution Building Blocks (SBBs). For example, a customer services capability may be required within an enterprise, supported by many SBBs, such as processes, data, and application software.

Solution Building Blocks (SBBs) represent components that will be used to implement the required capability. For example, a network is a building block that can be described through complementary artifacts and then put to use to realize solutions for the enterprise.

Enterprise Continuum

TOGAF includes the concept of the Enterprise Continuum, which sets the broader context for an architect and explains how generic solutions can be leveraged and specialized in order to support the requirements of an individual organization. The Enterprise Continuum is a view of the Architecture Repository that provides methods for classifying architecture and solution artifacts as they evolve from generic Foundation Architectures to Organization-Specific Architectures. The Enterprise Continuum comprises two complementary concepts: the Architecture Continuum and the Solutions Continuum.

Architecture Repository

Supporting the Enterprise Continuum is the concept of an Architecture Repository which can be used to store different classes of architectural output at different levels of abstraction, created by the ADM. In this way, TOGAF facilitates understanding and co-operation between stakeholders and practitioners at different levels.

By means of the Enterprise Continuum and Architecture Repository, architects are encouraged to leverage all other relevant architectural resources and assets in developing an Organization-Specific Architecture.

In this context, the TOGAF ADM can be regarded as describing a process lifecycle that operates at multiple levels within the organization, operating within a holistic governance framework and producing aligned outputs that reside in an Architecture Repository. The Enterprise Continuum provides a valuable context for understanding architectural models: it shows building blocks and their relationships to each other, and the constraints and requirements on a cycle of architecture development.

The major components within an Architecture Repository are as follows:

	The Architecture Metamodel describes the organizationally tailored application of an architecture framework, including a metamodel for architecture content.
	The Architecture Capability defines the parameters, structures, and processes that support governance of the Architecture Repository.
	The Architecture Landscape shows an architectural view of the building blocks that are in use within the organization today (e.g., a list of the live applications). The landscape is likely to exist at multiple levels of abstraction to suit different architecture objectives.
	The Standards Information Base (SIB) captures the standards with which new architectures must comply, which may include industry standards, selected products and services from suppliers, or shared services already deployed within the organization.
	The Reference Library provides guidelines, templates, patterns, and other forms of reference material that can be leveraged in order to accelerate the creation of new architectures for the enterprise.
	The Governance Log provides a record of governance activity across the enterprise.

Establishing and Maintaining an Enterprise Architecture Capability

In order to carry out architectural activity effectively within an enterprise, it is necessary to put in place an appropriate business capability for architecture, through organization structures, roles, responsibilities, skills, and processes.

ArchiMate®, an Open Group Standard, is an open and independent modelling language for enterprise architecture that is supported by different tool vendors and consulting firms. ArchiMate provides instruments to enable enterprise architects to describe, analyze and visualize the relationships among business domains in an unambiguous way.

The ArchiMate language defines three main layers (depicted with different colors in the examples in the next chapters):

1. The Business Layer offers products and services to external customers, which are realized in the organization by business processes performed by business actors.

2. The Application Layer supports the business layer with application services which are realized by (software) applications.

3. The Technology Layer offers infrastructure services (e.g., processing, storage, and communication services) needed to run applications, realized by computer and communication hardware and system software.

Enterprise Architecture Management, IT Architecture, standards and tools

The area of analysis and modeling of functional architecture, Enterprise Architecture are applied these design standards:

• ArchiMate and TOGAF (ArchiMate, an Open Group Standard, is an open and independent modelling language for enterprise architecture, supported by different tool vendors and consulting firms).

• BPMN (Business Process Modeling Notation) of consortium OMG (Object Management Group) - a standard for modeling business processes.

• CASE tools – Select Architect, Visual Paradigm, Archi (Free ArchiMate Modelling Tool), QPR Enterprise Architecture, BiZZdesign Architect, Sparx Enterprise Architect