Phase B/C/D - Architecture Definition


There is a lot of similarity in the flow of the phases B, C and D. Hence it is best to understand them together. An architecture has four main components - Business Architecture, Data Architecture, Application Architecture and Technology Architecture. These are defined during the Phase B, C and D.

The Phase B provides methods and tools for development of the Business Architecture that is in line with the agreed Architecture Vision. The Phase C describes the development of information system (data as well as application) to support the agreed Architecture Vision and the Business Architecture. Finally, Phase D describes the development of the Technology Architecture to support the Vision and the Business, Data and Application Architectures.

Objectives


In simple words, the objective of each of these phases is to define the corresponding baseline and target architectures, and then identify the gaps between them. The baseline architecture describes the current status of things and the target architecture is what we want it to be. The target architectures are developed based on the architecture vision, statement of architecture work and the stakeholder concerns - for this particular iteration of ADM.

The Business Architecture describes how the enterprise needs to operate in order to achieve the business goals defined in the Architecture Vision and Statement of Architecture Work. Data and Application Architectures define how the data rests and flows and is processed in the enterprise, in order to enable the Business Architecture. Whereas the Technology Architecture provides the technology components and services that enable the Data and Application Architectures.

Steps


Each of the three phases have very similar steps.

  • Select reference models, viewpoints, and tools
  • Develop Baseline and Target Architecture Descriptions
  • Perform Gap Analysis
  • Define candidate roadmap components
  • Resolve impacts across the Architecture Landscape
  • Conduct formal stakeholder review
  • Finalize the Architecture
  • Create Architecture Definition Document

Inputs


All three phases have a similar set of inputs. A lot of inputs to each architecture phase come from the architecture vision phase and the phases before it. For example, the Business Architecture Phase feeds into the Information Systems Architecture Phase, and so on.

  • Request for Architecture Work (Preliminary Phase)
  • Statement of Architecture Work (Architecture Vision)
  • Capability Assessment (Architecture Vision)
  • Communications Plan (Architecture Vision)
  • Organization Model for Enterprise Architecture (Preliminary Phase)
  • Tailored Architecture Framework (Preliminary Phase)
  • Architecture Vision
  • Architecture Repository and Enterprise Continuum (Continuously updated through iterations)
  • Draft Architecture Definition Document, containing the target and baseline architectures - populated in the Phase A(high level) and in the previous phases(detailed). For example, the Technology architecture will get the detailed business, data and application architectures (populated in the individual phases) and a high level technology architecture (populated in the Phase A).
  • Architecture roadmap for the previous phases.
  • Draft Architecture Requirements Specification, including: Gap analysis results and Relevant technical requirements
  • The relevant principles: Business principles, business goals, and business drivers / Data principles / Application Principles / Technology principles

Outputs


The outputs of the three phases are similar to each other.

  • Statement of Architecture Work, updated if necessary
  • Refined, updated or new Architecture Principles for that phase - if any
  • Draft Architecture Definition Document containing content updates:
    • Relevant Baseline Architecture (detailed), if appropriate
    • Relevant Target Architecture (detailed with Business Capabilities, Value Streams, and Organization Map as core artifacts)
    • Architecture views corresponding to the selected viewpoints, addressing key stakeholder concerns
  • Components of an Architecture Roadmap related to that phase
  • Draft Architecture Requirements Specification including content updates:

    Business

    • Gap analysis results
    • Technical requirements
    • Updated business requirements

    Data

    • Gap analysis results
    • Data interoperability requirements
    • Relevant technical requirements that will apply to this evolution of the architecture development cycle
    • Constraints on the Technology Architecture
    • Updated business requirements
    • Updated application requirements

    Application

    • Gap analysis results
    • Application interoperability requirements
    • Relevant technical requirements that will apply to this evolution of the architecture development cycle
    • Constraints on the Technology Architecture
    • Updated business requirements
    • Updated data requirements

    Technology

    • Gap analysis report
    • Requirements output from Phases B and C
    • Updated technology requirements