Automated Network State Checking: Insights from the Field#

Joe Shaw (REANNZ)

• Why: This is the best operational postmortem-style talk in the program: a full domestic-backhaul hardware refresh where every service had to be rehomed with evidence of continuity — and the response was to build a generalised, model-driven verification system rather than hand-check services. Deeply transferable to anyone doing migrations.
• What: REANNZ developed a generalised service model plus Python automation that reasons from live network data: it generated new configuration consistent with the new hardware and produced clear old-vs-new running-state comparisons at implementation time, iterated until it could verify even highly bespoke configurations. The talk demonstrates the system with case studies and the challenges overcome (from abstract only).
• How: A generalised service model driven off live network state (not hand-catalogued per-service checks), automated config generation, and diff-style continuity evidence produced at cutover — a closed feedback loop between intent, generation, and verification.
• Where applicable: REANNZ's R&E network context is specific, but the technique is general: any operator facing a hardware refresh, architecture change, or migration where per-service manual verification doesn't scale. Particularly relevant wherever bespoke legacy configurations make off-the-shelf assurance tools insufficient.