Reaching Fully Automated Backbone Networks: A Network Developer's Journey#

Eugen Serban & Bartek Bacal · Swisscom

• Why: A production SRv6 backbone at carrier scale, with the honest four-year delta between architecture PowerPoints and reality — squarely in this PM's WAN/protocol territory.
• What: Today: >3,000 devices (~10k target) running SRv6 orchestrated by NSO with zero manual CLI, >25k public-facing service instances (>150k target), and zero escalated major incidents. The candid part: standardization struggles, early engineering choices that hurt, toolkit woes, organizational and cultural hurdles (Dev vs Ops, Network Engineer vs Developer), and northbound processes that didn't adapt.
• How: A virtual dev stage with repeatable testing superseded earlier tooling; automatic documentation; a deliberately small standardized service catalog (L2VPN/EVPN, L3VPN, SRv6) so each component is replaceable. Open challenges named explicitly: true CI/CD, scale testing (YANG leafrefs and "for loops" causing exponential runtime growth), and closed-loop self-healing split into awareness → analysis → decision → execution.
• Where applicable: Swisscom-specific SP environment, NSO-centric. The org lessons (the hardest problems were not the network) and the scale-testing pitfalls transfer to any backbone automation program.