Key takeaways
- Statement: authorized work and commitments.
- Definition Document: described and justified architecture.
- Requirements Specification: verifiable conditions for implementation.
- Architecture Definition Document
- Describes the architecture, such as applications and their relationships. It contains artifacts such as a diagram.
- Architecture Requirements Specification
- Specifies verifiable conditions, such as the service responding within two seconds under agreed conditions.
- Architecture Roadmap
- Sequences work packages and transitions over time to reach the target.
Illustrative example: names, measures and decisions depend on the context. An artifact describes an aspect; a deliverable formalizes a result subject to review and approval.
Define the work and its result
The Statement of Architecture Work formalizes work to undertake: context, scope, approach, roles, deliverables, acceptance criteria, plan, and approval arrangements. It enables the relevant parties to agree on commitments. It is not a detailed list of every implementation choice.
The Architecture Definition Document describes architectural intent and states. It collects relevant domain views, Baseline, Target, or Transition Architectures, decision rationale, and gaps. Its primary role is descriptive and qualitative: it makes the intended organization and necessary changes understandable.
State verifiable requirements
The Architecture Requirements Specification identifies conditions implementation must satisfy. It may include standards, constraints, interoperability requirements, service levels, and operational conditions. The qualitative/quantitative distinction explains their dominant purpose; it does not prohibit measurements in a definition document. A requirement should be necessary, unambiguous, and verifiable through testing or measurement.
- Define explicit acceptance criteria.
- Connect each requirement to a need and a description.
- Distinguish work commitments from implementation constraints.
TERMS TO KNOW
The terms, in context.
- Requirement
- Necessary, verifiable condition that the solution must satisfy.
- Architecture Definition Document
- Coherent description of architectures and their rationale.