Exploring Cisco NSO: A Deep Dive into NETCONF/YANG (Part 2/3)

NETCONF and YANG — The Heart of Modern Network Automation

In part 1, we looked at why Cisco NSO has become an obvious choice for automating complex networks. In this part, we dive into the two protocols and modeling languages that make it possible: NETCONF and YANG.

From CLI to Structured Data

Traditionally, network engineers have configured devices via CLI or SNMP. This works — but scales poorly and is susceptible to human error. NETCONF replaces CLI with a structured, transactional interface over SSH where the configuration is XML data, not free text.

YANG — Model the Network as Code

YANG is the language we use to describe what a service or device should be able to do. With YANG models, NSO can abstract away differences between vendors and present a unified service model to the rest of the organization.

What it Gives You in Practice

• Rollbacks that actually work — entire transactions, not individual commands.
• A single source of truth for the configuration.
• The ability to generate CI/CD pipelines for network changes.

In the next part, we will go into the technical details of FASTMAP and reference counters — the mechanisms that make NSO unique.