Work on the “Yet Another Next Generation” (YANG) data modeling language started during 2004 at the 60th meeting of the IETF. YANG is used for creating schema for the configuration and state data transported by the content layer of NETCONF protocol.

Currently, YANG is a work-in-progress and is specified in four internet-drafts:

YANG – A data modeling language for NETCONF

Common YANG Data Types

Mapping YANG to Document Schema Definition Languages and Validating NETCONF Content

Guidelines for Authors and Reviewers of YANG Data Model Documents