TOGAF: Establishing Itself As the Definitive Method for Building Enterprise Architectures in the Commercial World, Page 2
The Architecture Development Method (ADM)
The ADM forms the core of TOGAF. It is the result of continuous contributions from a large number of architecture practitioners in The Open Group's Architecture Forum. At the heart of ADM is requirements management. The business, information systems, and technology architectures are always aligned with the business goals and requirements.
During preliminary work and Stage A, the architecture vision and the scope of the enterprise architecture effort are established, and key questions about the architecture are answered—how much information will be captured, how it will be maintained, how it will be used, and what kind of management buy-in is needed. Other questions include:
- How does an organization begin the process of modeling their enterprise?
- What notations should they use, and what is the method for building the models?
- What if a company only wants to do a slice of enterprise architecture—enough to meet their needs?
- How can existing architecture models be re-used?
In Stage C, we focus on the Information System (Data and Application) Architectures. TOGAF describes detailed steps for defining the application architecture, and how the applications use and manage the data and present information to users. For data architecture, TOGAF describes steps for defining the data entities relevant to the enterprise, using any appropriate data modeling technique (for example object role modeling, or traditional relational data modeling).
Stage D is concerned with developing the Technology Architecture (for which completion of the Business and IS architectures is a pre-requisite). It is represented by its own mini-framework, detailing how to architect the technology underpinnings of the organization.
One of the strengths of TOGAF is that the ADM also covers architecture implementation. During Stages E and F, you identify and prioritize the projects that will implement the target architecture, and in Sstage G, the projects are undertaken as a planned program of work and deliver the agreed architecture as an integrated set of architecture-compliant solution components.
The Enterprise Continuum
While the ADM specifies a process for building enterprise architecture, TOGAF also offers the Enterprise Continuum as a resource and philosophy for developing enterprise architecture through reusable building blocks. TOGAF's Enterprise Continuum (see Figure 2) specifies a progression for developing architectures and solutions using architecture building blocks (ABBs) and solution building blocks (SBBs), in a continuous, iterative fashion.
The Enterprise Continuum is composed of the Architecture and Solution Continuums. The Architecture Continuum provides guidance, direction, and support to use the Solutions Continuum to build your technology architecture. The Solutions Continuum defines the solutions that deliver the architecture, and include off-the-shelf solutions and an organization's own in-place solutions.
The TOGAF ADM guides users through the left to right progression from the general architectures and solutions (on the left), to organization-specific ones (on the right). The Architecture Continuum specifies the Foundation Architecture as the starting point for the architecture effort, then moves through common systems architectures (for example, a generic security architecture), and industry-specific architectures (for example, a Retail Industry Architecture), to reach the organization-specific architecture (on the right).
During the preliminary stage of ADM, users establish how much of its Foundation Architecture can be established from what is already in place in the organization. TOGAF provides a Foundation Architecture to help users get started, embodied in the Technical Reference Model (TRM) and Standards Information Base (SIB). Once an organization has been through its first TOGAF ADM iteration, its own Technology Architecture forms part of its Foundation Architecture for the next cycle.
Figure 2. TOGAF Enterprise Continuum, showing the progression that leads to the increasing refinement of the organization-specific architecture. Source: Popkin Software & The Open Group
Why TOGAF Works
As an enabler of enterprise architecture, TOGAF provides the following benefits:
- Proven Method—TOGAF offers a proven method that is the result of years of research and development by the world's leading enterprise architects.
- Common Vocabulary—TOGAF guides architects in using a standard taxonomy for business, information systems, and technology modeling. This shared vocabulary means that everyone in an organization can read and understand the information.
- Communication—Models of the enterprise architecture give visual representation to business concepts, and, when published on the corporate intranet, disseminate knowledge of the business to the workforce.
- Command Decisions—A business-focused enterprise architecture provides knowledge about an organization and enables managers to make better-informed decisions.
- Reduced complexity—A well developed architecture leads to a better integrated solution portfolio, fewer interfaces, increased data sharing, improved reliability of the solutions, and easier maintenance.
- Business-IT alignment—The business focus of the architecture development process and the strong emphasis on the need for the implemented solution to be architecture-compliant together will help ensure that IT solutions are aligned to the needs of the business.
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