Versioned Services for Network Automation#

James Henderson – Ductus

• Why: Automation systems are usually written as if the standards they implement never change; this offers a clean, adoptable pattern for managing service intent across time — with EVPN as the running example.
• What: A pattern combining named service types, semantic versions, and managed features — where a feature is a flag with metadata (introduced-in, standard-in, when-disabled fallback behavior, conflicts-with) rather than a bare code switch — plus cascading (hierarchical) types that control which features a service may use. Versioned packages pin each service version to an exact code commit, so rollbacks know which implementation to return to, and individual features can migrate independently across services (the talk shows a mid-migration state where one customer's RT is migrated and another's RD is not).
• How: Semantic versioning for services (major = breaking contract change, minor = golden-config update with new feature, patch = code fix); the type carries classification, the version carries which flags apply.
• Where applicable: General technique for any golden-config/automation platform, org-agnostic despite the EVPN examples. Also argued (briefly) as a prerequisite for safe AI agents in network ops — reversibility and transparency — which pairs naturally with the agentic sessions below.