NETCONF (Network Configuration Protocol) is a standard used for network device configuration, and it utilizes YANG (Yet Another Next Generation) as a data modeling language. Cisco IOS XE and Cisco NX-OS support NETCONF and YANG to automate the configuration and management of network devices across a network. YANG defines the data models, while NETCONF provides the protocol to manipulate these models. Reference: Cisco DevNet Documentation - NETCONF and YANG IETF RFC 6241 - NETCONF Protocol IETF RFC 6020 - YANG Data Modeling Language