YANG (data modeling language)

YANG (data modeling language)
Name	YANG
Title	YANG (data modeling language)
Developer	Internet Engineering Task Force
Initial release	2006
Latest release	2016
License	IETF Trust
Website	RFC 6020

YANG (data modeling language) is a data modeling language standardized for the Internet Engineering Task Force used to model configuration and state data manipulated by network management protocols. It was developed to provide a structured, extensible way to describe hierarchical configuration, operational state, and administrative actions for networked devices and services deployed by organizations such as AT&T, Cisco Systems, and Juniper Networks. The language complements protocols and frameworks from bodies like the Internet Assigned Numbers Authority, International Telecommunication Union, and European Telecommunications Standards Institute.

Overview

YANG was first standardized through documents produced by working groups within the Internet Engineering Task Force, including contributions from engineers affiliated with Nokia, Ericsson, and Huawei. The design emerged in the context of network management efforts that involved standards from TeleManagement Forum, Open Networking Foundation, and the IETF NETMOD Working Group. YANG provides a formal schema for data models that map to management protocols including NETCONF, RESTCONF, and management frameworks used by vendors such as Arista Networks and Ciena Corporation.

Language Concepts and Structure

The core concepts of YANG include modules, containers, lists, leafs, typedefs, groupings, and augmentations, and these elements were influenced by modeling precedents from standards like SNMP MIBs and schema languages such as XML Schema and YAML. YANG's type system and semantic constraints allow interoperability between implementations from vendors including Cisco Systems, Huawei, Juniper Networks, and service providers like Verizon Communications and Deutsche Telekom. The language supports annotations and extensions used in ecosystems around Red Hat, Microsoft, and cloud providers like Amazon Web Services where configuration models must interoperate with orchestration systems and OpenStack deployments.

Module and Submodule Organization

YANG organizes models into modules and submodules with namespaces and prefixes; this module architecture parallels practices adopted by standards bodies such as IETF, 3rd Generation Partnership Project, and ETSI. Modules declare imports and includes that reference models from organizations including IEEE, IANA, and industry consortia like the ONF. Large vendors and vendors' open-source projects, such as those by Cisco Systems, Juniper Networks, Arista Networks, and Barefoot Networks, publish module catalogs and repositories to facilitate reuse across products and management platforms used by carriers like Sprint Corporation and T-Mobile US.

Tooling and Implementation

A vibrant tooling ecosystem supports YANG, with parsers, validators, code generators, and test frameworks from projects and organizations such as OpenDaylight, FRRouting, YangModels/yang, pyang, and vendors including Cisco Systems and Juniper Networks. Integration with continuous integration and automation platforms developed by GitHub, GitLab, and cloud providers like Google Cloud Platform enables model validation in deployment pipelines used by enterprises including Facebook and Netflix. Commercial and open-source network orchestration systems from Ansible, SaltStack, and Puppet (software) incorporate YANG model support for device configuration across equipment from Ciena Corporation and Huawei.

Standards, Extensions, and Related Technologies

YANG's standardization is documented across multiple IETF RFCs and complemented by extensions and companion specifications related to NETCONF, RESTCONF, data modeling for telemetry such as gNMI, and encoding mappings for JSON and XML. The model-driven architectures used by operators such as AT&T and NTT align YANG with orchestration initiatives from ETSI and open-source platforms including ONAP and Open Networking Foundation projects. Interoperability testing and conformance programs from vendor consortiums and standards bodies such as Broadband Forum and Metro Ethernet Forum help certify implementations from suppliers like Cisco Systems, Juniper Networks, and Ericsson.

Use Cases and Deployment Examples

YANG is deployed for device configuration, operational telemetry, service orchestration, and intent-based networking in environments run by cloud operators like Amazon Web Services, carriers including Verizon Communications and Deutsche Telekom, and large enterprises such as Google LLC and Microsoft. Use cases include automated provisioning workflows in systems developed by AT&T and Telefonica, closed-loop assurance in platforms from Vodafone Group and Orange S.A., and vendor-neutral model catalogs maintained by groups like YangModels/yang and open-source controllers such as OpenDaylight.

Category:Data modeling languages