YANG Models

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The YANG (Yet Another Next Generation) modeling language is used for configuring and managing data in networking, both in a configuration and operational state. Created by the NETMOD working group of the IETF (Internet Engineering Task Force), it is defined in several technical documents published by the IETF, RFC 6020 and RFC 7950. YANG is used by networking protocols such as NETCONF and RESTCONF.

These models can be represented by trees for easier readability using tools like Pyang, a Python tool used to validate, transform, and generate YANG models. Below is a sample of a YANG tree from the IETF.

     +--rw interfaces
    |    +--rw interface* [name]
    |         +--rw name                                               string
    |         +--rw description?                                 string
    |         +--rw type                                                  identityref
    |         +--rw enabled?                                        boolean
    |         +--rw link-up-down-trap-enable?   enumeration

 In the context of Open RAN, YANG is particularly important to the m-plane, which falls under Working Group 4 and the Open Fronthaul interface as the m-plane relies on NETCONF. Due to the standardization and flexibility the YANG models provide, they are a great way to enable interoperability.