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Software Architecture Guide

TOGAF Phase C: Application Architecture

Explanation

Section titled “Explanation”

Phase C of the TOGAF Architecture Development Method covers two architectures: data and application. This article covers the application part.

Objectives

The first objective is a target application architecture. It must enable the business architecture and the architecture vision. The second objective is to find candidate roadmap components. These come from the gaps between the baseline (today’s applications) and the target.

Place in the method

TOGAF does not fix the order inside Phase C. A team can do data first, application first, or both at the same time. Phase C follows the same rhythm as Phases B and D. The team documents the baseline, designs the target, and then performs a gap analysis. The finished data and application architectures feed the Technology Architecture in Phase D.

Roadmap and impacts

The candidate roadmap components add up to an application roadmap. It sets priorities for the activities in the coming phases. Once the application architecture is final, the team must also understand its wider impacts across the architecture landscape.

Outputs

The Architecture Definition Document is the core descriptive artifact of the method. Phase C results are captured in it. Typical content includes:

  • The Application Portfolio Catalog, a list of all applications in the enterprise.
  • The Interface Catalog, which scopes and documents the interfaces between applications.
  • Matrices, such as the Application/Organization matrix. It relates applications to organizational units.
  • The Application Communication diagram. It shows application components and the interfaces between them.
  • The Software Engineering diagram. It breaks applications into packages, modules, services and operations from a development perspective.
  • The Application Migration diagram. It shows how application components move from baseline to target.

Example

Section titled “Example”

A company wants to support a new online ordering process. The team lists its current applications and the interfaces between them. It then designs the target set of applications. The gap analysis shows that no application handles order tracking. The team records “add order tracking” as a candidate roadmap component. It then checks which other parts of the landscape this change affects.

Application architecture work inside Phase C, between Phases B and D

Diagram source 
flowchart LR
  B[Phase B: Business Architecture] --> C[Phase C: Data and Application Architecture]
  C --> D[Phase D: Technology Architecture]
  subgraph App[Application part of Phase C]
    A1[Document baseline] --> A2[Design target] --> A3[Gap analysis] --> A4[Candidate roadmap components]
  end
  C --- App

Checks

Section titled “Checks”
  • The document states a target application architecture that enables the business architecture and the architecture vision.
  • Baseline and target application architectures are both described, and a gap analysis between them exists.
  • Candidate roadmap components are derived from the gaps and feed a prioritized application roadmap.
  • An application portfolio catalog and an interface catalog are present.
  • Wider impacts of the finalized application architecture across the landscape are addressed.
Section titled “Related”

Sources

Section titled “Sources”