rd has a provision to allow data models to be extended. For any update to the data model resulting from a later version of 1588 or some specific profile, the original 1588 model is imported, and additional elements added with the augment YANG DML keyword. It is the authors' expectation that as RFC 8575 becomes established as a standard, it will be improved to include elements and datasets required by IEEE 1588-2019 as well as by different profiles spe- cified by ITU-T recommendations (such as G.8275.1, G.8275.2, and SO on). So, for now, RFC 8575 proposes the hierarchy of a YANG module for IEEE 1588-2008, which en- compasses query and configuration of device, timing port, and clock datasets. Query and configura- tion of clock information includes the following: Clock dataset attributes in a clock node, such as Current dataset, Parent dataset, Default dataset, Time Properties dataset, and Transparent Clock Default dataset (see Chapter 7 for details of these datasets). Port-specific dataset attributes, such as Port dataset and Transparent Clock Port dataset. Again, see Chapter 7 for details of these datasets. In IEEE 1588-2008, each member of the various PTP datasets is classified as one of the following: Configurable: The value can be read and written by the management node (an example is the domain number of the clock). Dynamic: The value can only be read, but the value is updated by normal PTP protocol opera- tions (an example is the clockClass of the Default dataset). Static: The value can only be read, and the value typically does not change (an example is the two-step flag). For details on the classification of each PTP dataset, refer to 1588-2008 or the overview of the vari- ous datasets in Chapter 7. To handle the situation where an element can change between categories, RFC 7950 specifies a de- viation mechanism whereby the category of the field can be updated. In a future implementation, if a read-only element of a dataset becomes read-write and the management node can update it, then the YANG model can be