n ISO 8601. There is a working group within the IETF called Timing over IP Connection and Transfer of Clock (TICTOC), which is responsible for aspects of timing for the Internet technologies. The TICTOC WG is the driving force behind about four or five published (but currently still draft) RFCs related to PTP and timing. Most importantly, TICTOC currently defines a PTP profile for corporate net- works known as the Enterprise PTP Profile. An example of likely adopters is financial trading companies, where more precise time accuracy is needed than available from current implementa- tions of NTP. The contributions of TICTOC also cover the areas of defining an SNMP MIB and YANG data model for PTP as well as RFCs on PTP security and multipath synchronization. Draft RFC 8575 defines a YANG model to configure PTP clocks as specified in IEEE 1588 (for the default profiles). Please refer to "Chapter 12. Operating and Verifying Timing Solutions", for more details on PTP monitoring, management, and assurance. Chapter 7 offers further information on the Enterprise PTP profile, and there are additional references at the end of the chapter. Another relevant part of the IETF is in the area of deterministic networking with the Deterministic Networking (DETNET) Working Group. This working group focuses on mechanisms to define data paths that are bounded in latency, packet loss, PDV (jitter), and reliability over layer 2 and layer 3 networks. The DETNET WG collaborates with IEEE TSN to define TSN for next-generation tech- nologies (such as 5G) and industrial automation. Based on the work of IEEE TSN, which is re- sponsible for layer 2 operation, the DETNET WG acts to define a common architecture for both layer 2 and layer 3. Of course, beyond the specialized areas outlined here, the IETF is the overarching guiding hand be- hind much of the Internet-, IP-, and MPLS-based transport networks that connect everything to- gether. These technologies are key components of transport networks, not only to carry timing sig- nals but also to 