The TOGAF Standard
The TOGAF® Standard, 10th Edition — Architecture Development Method
The Open Group
Chapter 1: Introduction
This chapter introduces the Architecture Development Method (ADM) cycle, adapting the ADM, architecture scope, and architecture integration.
1.1 ADM Overview
The TOGAF ADM describes a method for developing and managing the lifecycle of an Enterprise Architecture, and forms the core of the TOGAF Standard.
It integrates elements of the TOGAF Standard, as well as other available architectural assets, to meet the business needs of an organization.
1.1.1 The ADM, Enterprise Continuum, and Architecture Repository
The Enterprise Continuum provides a framework and context to support the leverage of relevant architecture assets in executing the ADM. These assets may include Architecture Descriptions, models, and patterns taken from a variety of sources, as explained in the TOGAF Standard — Architecture Content.
The Enterprise Continuum categorizes architectural source material — both the contents of the organization’s own enterprise repositories and the set of relevant, available reference models and standards in the industry.
The practical implementation of the Enterprise Continuum will typically take the form of an Architecture Repository (see the TOGAF Standard — Architecture Content) that includes reference architectures, models, and patterns that have been accepted for use within the enterprise, and actual architectural work done previously within the enterprise. The architect would seek to re-use as much as possible from the Architecture Repository that was relevant to the project in hand. (In addition to the collection of architecture source material, the repository would also contain architecture development work-in-progress.)
At relevant places throughout the ADM there are reminders to consider which, if any, architecture assets from the Architecture Repository the architect should use. In some cases — for example, in the development of a Technology Architecture — this may be the TOGAF Foundation Architecture. In other cases — for example, in the development of a Business Architecture — it may be a reference model for e-Commerce taken from the industry at large.
The criteria for including source materials in an organization’s Architecture Repository will typically form part of the Enterprise Architecture Governance process. These governance processes should consider available resources both within and outside the enterprise in order to determine when general resources can be adapted for specific enterprise needs and also to determine where specific solutions can be generalized to support wider re-use.
While using the ADM, the architect is developing a snapshot of the enterprise’s decisions and their implications at particular points in time. Each iteration of the ADM will populate an organization-specific landscape with all the architecture assets identified and leveraged through the process, including the final organization-specific architecture delivered.
Architecture development is a continuous, cyclical process, and in executing the ADM repeatedly over time, the architect gradually adds more and more content to the organization’s Architecture Repository. Although the primary focus of the ADM is on the development of the enterprise-specific architecture, in this wider context the ADM can also be viewed as the process of populating the enterprise’s own Architecture Repository with relevant re-usable building blocks taken from the "left", more generic side of the Enterprise Continuum.
In fact, the first execution of the ADM will often be the hardest, since the architecture assets available for re-use will be relatively scarce. Even at this stage of development, however, there will be architecture assets available from external sources such as the TOGAF Standard, as well as the IT industry at large, that could be leveraged in support of the effort.
Subsequent executions will be easier as more and more architecture assets become identified, are used to populate the organization’s Architecture Repository, and are thus available for future re-use.
1.1.2 The ADM and the Foundation Architecture
The ADM is also useful to populate the Foundation Architecture of an enterprise. Business requirements of an enterprise may be used to identify the necessary definitions and selections in the Foundation Architecture. This could be a set of re-usable common models, policy and governance definitions, or even as specific as overriding technology selections (e.g., if mandated by law). Population of the Foundation Architecture follows similar principles as for an Enterprise Architecture, with the difference that requirements for a whole enterprise are restricted to the overall concerns and thus less complete than for a specific enterprise.
It is important to recognize that existing models from these various sources, when integrated, may not necessarily result in a coherent Enterprise Architecture. "Integratability" of Architecture Descriptions is considered in Section 1.7.
1.1.3 ADM and Supporting Guidelines and Techniques
The application of the TOGAF ADM is supported by an extended set of resources — guidelines, templates, checklists, and other detailed materials. These are included in:
■ The TOGAF Standard — ADM Techniques
■ TOGAF Series Guides — the Guidance part of the Standard (guidance material on how to use and adapt the TOGAF Standard for specific needs)
■ White Papers and Guides published by The Open Group, classified and referenced in the TOGAF Library (see www.opengroup.org/togaf-library)
The individual guidelines and techniques are described separately so that they can be referenced from the relevant points in the ADM as necessary, rather than having the detailed text clutter the description of the ADM itself.
1.2 Architecture Development Cycle
1.2.1 Key Points
The following are the key points about the ADM:
■ The ADM is iterative, over the whole process, between phases, and within phases (see the TOGAF Standard — ADM Techniques)
For each iteration of the ADM, a fresh decision must be taken as to:
— The breadth of coverage of the enterprise to be defined
— The level of det...