NETCONF and YANG: Automating Networks with Data Models

April 15, 2026·2 min read·295 words

NETCONF (RFC 6241) + YANG (RFC 7950) are the modern standards for programmatic multi-vendor configuration. NETCONF is a protocol (XML/SSH), while YANG is a data modeling language. They are natively supported by Cisco IOS-XE/NX-OS, Juniper Junos, Arista EOS, and Nokia. They are gradually replacing CLI parsing.

Why NETCONF/YANG

CLI parsing is fragile (syntax changes break scripts)
NETCONF uses structured XML for reliable parsing
YANG provides schemas for validation before deployment
Atomic transactions (commit/rollback)
Multi-vendor standard

NETCONF

Transport: SSH port 830 or TLS 6513
Payload: structured XML
Operations: get, get-config, edit-config, copy-config, delete-config, lock, unlock, close, kill, commit
Candidate/running/startup datastores
Capability advertisement

YANG

Modeling language (similar to JSON Schema)
Hierarchical structure: containers, lists, leaves
Types: string, int, boolean, enum
Standards: OpenConfig (multi-vendor), IETF, vendor-specific (Cisco-YANG, Junos-YANG)
Version: YANG 1.1 (RFC 7950)

OpenConfig: multi-vendor standard

Consortium: Google, Microsoft, Apple, and network operators
Cross-vendor models: interfaces, BGP, routing, LLDP
Used by Cisco, Arista, Juniper, and Nokia
Vision: write-once, run-anywhere automation

NETCONF + Python (ncclient) example

from ncclient import manager
with manager.connect(host='10.0.0.1', port=830, username='admin', password='pass', hostkey_verify=False) as m:
config = m.get_config(source='running').data_xml
print(config)

gNMI

gRPC Network Management Interface: a modern gRPC-based alternative
Higher performance than NETCONF/XML
Native streaming telemetry
Supported by Cisco IOS-XE 16.10+, Arista, and Nokia
Growing adoption in 2026

Streaming telemetry

Push model: the device sends metrics regularly
Replaces SNMP polling
Transport: gNMI, gRPC, Kafka
Collectors: Prometheus, InfluxDB, Grafana

Tools

ncclient (Python): NETCONF library
pyang: YANG model validation
pyangbind: YANG → Python objects
gnmic: gNMI CLI client
gnxi: gNMI + gNOI from Google

Adoption in France in 2026

ISPs/network operators: mature NETCONF + OpenConfig adoption
Large enterprises: migration underway
SMEs and mid-sized companies: still using CLI + Netmiko/Ansible
Evolution: slow but inevitable

Order from OPTINOC

NETCONF/YANG + gNMI training. Streaming telemetry deployment. OpenConfig integration. Quote within 48 hours.