Modernizing Workflows as Old as the Railways: Operationalizing Network Automation#

Leo Fleskes · Network Automation Architect — DB Systel GmbH (with Gerasimos Tzakis, Network to Code)

• Why: The best data-quality war story in the program — two years of IPAM/inventory cleanup before any automation was possible at a 2,500+-router railway WAN. IPAM data hygiene is directly in this PM's wheelhouse.
• What: Building a Single Source of Truth uncovered the brownfield mess: empty locations, "Düsseldorf" vs "Dusseldorf", VRF mismatches, DNS misconfigurations, missing or mis-attributed prefixes. A dedicated cleanup team plus daily issue reports produced +25% documented IP addresses and, crucially, organizational momentum. A VPN rollout that took 70 minutes across four teams now takes 25 across one.
• How: Stage-by-stage: SoR interaction through small Nautobot jobs (allocation 25 → 5 min), configuration through an NSO service fed by the Nautobot job (30 → 1 min), documentation still manual. Platform scaling follows Conway: weekly integration meetings, shared responsibility split between platform team and device-owner teams, PRs reviewed from both sides.
• Where applicable: Deutsche Bahn-scale brownfield WAN; the sequencing (data first, MVP workflows, blameless cleanup culture) and the "give us a 'let's fix it' mentality" tactic transfer to any brownfield IPAM/SoT effort.