Architecture Review & Validation - System Architecture

Architecture Review Types

Review Type	Trigger	Participants	Key Questions
Architecture concept review	Before detailed design start	OEM architect + Safety + Security + Network	Is the architecture concept sound? Major risks identified?
Interface baseline review	Before Tier-1 design start	OEM + all Tier-1 suppliers	Are all interfaces complete? ASIL allocated? No ambiguity?
Architecture completion review	After architecture freeze	Full project team	All requirements allocated? Resource budgets met? FMEA closed?
Safety architecture review	Before ASIL-critical design start	Safety engineer + independent assessor	ASIL decomposition valid? Safety measures complete?
Integration readiness review	Before HW/SW integration	Architect + Integration team	All interfaces implemented? Test vectors prepared?

Architecture Review Checklist

YAMLarch_review_checklist.yaml

# Architecture review checklist: pre-Tier-1 design start
checklist:
  requirements_allocation:
    - "100% of system requirements allocated to architecture element [ASPICE SYS.3 BP1]"
    - "Backward traceability: all components justified by at least one requirement"
    - "ASIL level specified for every safety-relevant component"

  interface_completeness:
    - "All inter-ECU signals defined: name, ID, encoding, cycle, ASIL, E2E profile"
    - "All CAN IDs unique on each bus segment (no ID collision)"
    - "All SOME/IP service IDs and method IDs unique in vehicle namespace"
    - "Timeout behaviour specified for all safety-critical signals"

  resource_budgets:
    - "CPU utilisation < 70% for all ECUs (sum of WCET/period)"
    - "ROM allocation < 80% for all ECUs"
    - "RAM allocation < 75% for all ECUs"
    - "All CAN bus segments < 60% load"

  safety:
    - "All ASIL-D requirements decomposed or single-ECU justified"
    - "Independence arguments documented for all decompositions"
    - "Architecture-level FMEA complete; all RPN > 100 addressed"

  security:
    - "Security zone model complete; trust boundaries defined"
    - "Cryptographic architecture specified (secure boot, OTA signing)"
    - "No direct path from external zone to safety-critical zone"

Summary

Architecture reviews are most effective when they are checklist-driven rather than open-ended discussions. The checklist converts subjective quality judgments ("does this look right?") into objective pass/fail items ("is CPU utilisation below 70% for all ECUs?"). The interface baseline review is the most critical review in a supplier development model: it is the last opportunity to catch interface specification gaps before Tier-1 suppliers begin ECU design. Gaps discovered after Tier-1 design start require specification change requests, potentially triggering contract amendments and delivery delays. A one-week delay in the architecture review to resolve interface ambiguities is worth months of integration rework.

🔬 Deep Dive — Core Concepts Expanded

This section builds on the foundational concepts covered above with additional technical depth, edge cases, and configuration nuances that separate competent engineers from experts. When working on production ECU projects, the details covered here are the ones most commonly responsible for integration delays and late-phase defects.

Key principles to reinforce:

Configuration over coding: In AUTOSAR and automotive middleware environments, correctness is largely determined by ARXML configuration, not application code. A correctly implemented algorithm can produce wrong results due to a single misconfigured parameter.
Traceability as a first-class concern: Every configuration decision should be traceable to a requirement, safety goal, or architecture decision. Undocumented configuration choices are a common source of regression defects when ECUs are updated.
Cross-module dependencies: In tightly integrated automotive software stacks, changing one module's configuration often requires corresponding updates in dependent modules. Always perform a dependency impact analysis before submitting configuration changes.

🏭 How This Topic Appears in Production Projects

Project integration phase: The concepts covered in this lesson are most commonly encountered during ECU integration testing — when multiple software components from different teams are combined for the first time. Issues that were invisible in unit tests frequently surface at this stage.
Supplier/OEM interface: This is a topic that frequently appears in technical discussions between Tier-1 ECU suppliers and OEM system integrators. Engineers who can speak fluently about these details earn credibility and are often brought into critical design review meetings.
Automotive tool ecosystem: Vector CANoe/CANalyzer, dSPACE tools, and ETAS INCA are the standard tools used to validate and measure the correct behaviour of the systems described in this lesson. Familiarity with these tools alongside the conceptual knowledge dramatically accelerates debugging in real projects.

⚠️ Common Mistakes and How to Avoid Them

Assuming default configuration is correct: Automotive software tools ship with default configurations that are designed to compile and link, not to meet project-specific requirements. Every configuration parameter needs to be consciously set. 'It compiled' is not the same as 'it is correctly configured'.
Skipping documentation of configuration rationale: In a 3-year ECU project with team turnover, undocumented configuration choices become tribal knowledge that disappears when engineers leave. Document why a parameter is set to a specific value, not just what it is set to.
Testing only the happy path: Automotive ECUs must behave correctly under fault conditions, voltage variations, and communication errors. Always test the error handling paths as rigorously as the nominal operation. Many production escapes originate in untested error branches.
Version mismatches between teams: In a multi-team project, the BSW team, SWC team, and system integration team may use different versions of the same ARXML file. Version management of all ARXML files in a shared repository is mandatory, not optional.

📊 Industry Note

Engineers who master both the theoretical concepts and the practical toolchain skills covered in this course are among the most sought-after professionals in the automotive software industry. The combination of AUTOSAR standards knowledge, safety engineering understanding, and hands-on configuration experience commands premium salaries at OEMs and Tier-1 suppliers globally.