Handbook
V-Model — major processes & flow maps
Left side descends (decomposition); right side ascends (integration and verification). Dotted arrows show traceability pairing.
1. V-Model structure (classic)
Left side descends (decomposition); right side ascends (integration and verification). Dotted arrows show traceability pairing.
2. Traceability flow
3. Test-level gate decision
4. Change impact (V-Model perspective)
A change to a requirement potentially impacts design, implementation, and tests at multiple V-levels.
5. Phases A–F (V-Model mapping)
| Blueprint phase | V-Model locus |
|---|---|
| A Shape | Stakeholder needs; concept of operations |
| B Plan | Requirements analysis + acceptance test planning (paired) |
| C Build | System design → detailed design → implementation (left side descent) |
| D Verify | Unit → integration → system testing (right side ascent) |
| E Release | Acceptance testing; deployment readiness |
| F Learn | Operational validation; field feedback; lessons for next cycle |
6. Flow details (walkthrough)
V-Model structure — The V is not just a picture; it encodes a discipline. Each left-side level produces specifications that the corresponding right-side level will verify. Test planning happens during design, not after coding. This early pairing catches specification issues before they become implementation defects.
Traceability — The requirement-to-evidence chain is the V-Model's core deliverable. Every requirement must be testable, every test must trace to a requirement, and every test result must be recorded. Gaps in traceability indicate either missing tests or unnecessary requirements.
Test-level gates — Each V-level has an entry check (test readiness) and exit check (test results). Failures feed back to the corresponding development level for resolution, not to a generic "fix bugs" phase.
Change impact — Changes in the V-Model are expensive because they ripple across levels. Impact analysis must consider all affected V-levels: a requirement change may require design updates, code changes, and retesting at unit, integration, system, and acceptance levels.
7. Authoritative sources & further reading
- Wikipedia — V-model (software development) — Stable overview.
- Wikipedia — Verification and validation — V&V concepts.
- ISO 26262 (catalogue) — Automotive functional safety (V-Model-aligned).
- IEC 62304 (catalogue) — Medical device software lifecycle.
Full curated list: External reference URLs (methodology guides).