Phase C: Application Architecture Knowledge-Based Study

Study notes

1. Understanding Phase C in the TOGAF ADM

   In the TOGAF Standard, 10th Edition, Phase C: Information Systems Architectures addresses the architecture domains that support the Business Architecture developed in Phase B. Phase C is divided into two distinct, parallel or sequential sub-domains:

   • Data Architecture: Defines the major types and sources of data necessary to support the business.
   • Application Architecture: Defines the kinds of application systems required to process the data and support the business.

   It is important to emphasize that Phase C: Application Architecture does not define application system design or software engineering specifics (such as coding constructs or internal algorithms). Instead, it focuses on identifying logical application components, their interactions, boundaries, and how they deliver business capabilities.

   Key Objectives of Application Architecture

   The primary objectives of the Application Architecture phase include:

   • Developing the Target Application Architecture that describes how application systems enable business processes and manage data.
   • Analyzing gaps between the Baseline Application Architecture and the Target Application Architecture.
   • Identifying candidate roadmap components and architecture alternatives to resolve identified gaps.

   Standard Steps in Phase C (Application Architecture)

   Developing the Application Architecture follows a structured sequence within the Architecture Development Method (ADM):

   1. Select Reference Models, Viewpoints, and Tools: Review architectural principles, choose relevant industry or organizational reference models, and determine appropriate modeling techniques.
   2. Develop Baseline Application Architecture Description: Document existing application systems, their functional boundaries, and integration points to the extent required to support change.
   3. Develop Target Application Architecture Description: Model the future state of application capabilities, services, and communication protocols.
   4. Perform Gap Analysis: Compare baseline and target models to identify missing, redundant, or changed application capabilities.
   5. Define Candidate Roadmap Components: Prioritize transitions and identify discrete work packages or components for Phase E (Opportunities and Solutions).
   6. Resolve Impacts across the Architecture Landscape: Evaluate ripple effects on business, data, and technology domains.
   7. Conduct Stakeholder Review and Finalize: Ensure alignment with business drivers and requirements.
   8. Create the Architecture Definition Document: Finalize models and architectural viewpoints.

   Essential Catalogs, Matrices, and Diagrams

   Common architectural artifacts developed in this phase include:

   • Catalogs: Application Portfolio Catalog, Interface Catalog.
   • Matrices: System/Organization Matrix, Application/Function Matrix, Application/Data Matrix.
   • Diagrams: Application Communication Diagram, Application and User Location Diagram, System Migration Diagram.

   Alignment with Architecture Capability and Governance

   When establishing and operating an Enterprise Architecture Capability, Phase C deliverables play a critical role in continuous governance:

   • Application Portfolio Rationalization: The Application Architecture provides standard classification schemes that governance boards use to eliminate duplicate software investments and reduce operational debt.
   • Architecture Contracts: Target application definitions serve as baseline specifications against which implementation projects are evaluated for architecture compliance.
   • Boundary Definition: Clearly distinguishing between business services and application services prevents vendor lock-in and aligns software procurement directly with corporate business capabilities.

   Governance bodies utilize Phase C outputs to ensure interoperability standards and security constraints are consistently enforced across multi-vendor environments.

   Knowledge Assessment Questions

   Test your understanding of Phase C: Application Architecture with the following multiple-choice questions.

   Question 1

   According to the TOGAF Standard, 10th Edition, which of the following best describes the core scope of the Application Architecture domain in Phase C?

   • A) Designing detailed internal software algorithms, database indexing, and user interface components.
   • B) Defining the major kinds of application systems needed to process data and support the business capabilities.
   • C) Specifying the hardware platforms, operating systems, and network topology required to host software solutions.
   • D) Defining the business goals, strategic drivers, and operational organizational units of the enterprise.

   Explanation: The correct answer is B. In TOGAF Phase C, Application Architecture defines the logical application systems and their interactions required to support business capabilities. Option A describes detailed software implementation, Option C corresponds to Phase D (Technology Architecture), and Option D relates to Phase B (Business Architecture).

   Question 2

   Which artifact is primarily developed during Phase C: Application Architecture to depict interactions and data flows between application systems?

   • A) Business Footprint Diagram
   • B) Network Computing/Hardware Diagram
   • C) Application Communication Diagram
   • D) Requirements Realization Matrix

   Explanation: The correct answer is C. The Application Communication Diagram models the communication paths, interfaces, and boundary interactions between applications. Option A belongs to Phase B, Option B belongs to Phase D, and Option D is used in Requirements Management.