sion 2 (IGMPv3 optional), although SMPTE allows IPv6 as well. Each requires the delay-request/response mechan- ism (Annex J.3 from IEEE 1588-2008) as the path delay measurement mechanism, although both SMPTE and AES optionally support the P2P delay measurement mechanism (Annex J.4 from 1588- 2008) as well. They both support ordinary and boundary clocks and the default 1588 BMCA algorithm. Both profiles support a different range of message rates, with SMPTE requiring a higher rate for Sync and Announce, but there is substantial overlap in the ranges allowed. Because of these similar- ities, it is possible, by careful selection of the profile parameters, to combine them on the same network. At the agreed point that fits within both profiles, media streams of different types can be synchron- ized by using a single, common PTP clock distribution system (see AES-R16-2016, "PTP paramet- ers for AES67 and SMPTE ST 2059-2 interoperability"). Note that a new edition of the SMPTE ST 2059-2 was due for publication at the end of 2020 but at the time of writing is not yet published. It is expected to contain the following changes: New defaults to better align SMPTE and AES67 profiles Clarified communications modes of multicast, unicast, and mixed Makes use of the traceable flag Removes some inappropriate terms. These two standards (along with others relating to the audio and video itself) are a very important component of industries related to broadcasting. 7.5.1 PTP Enterprise Profile (Draft RFC) The Enterprise Profile is a proposed standard by the Timing over IP Connection and Transfer of Clock (TICTOC) Working Group of the IETF (https://tools.ietf.org/wg/tictoc/), which is responsible for about four published RFCs related to PTP and timing. This draft document defines a PTP profile targeted for large enterprise networks, such as those found in large financial organizations. See Chapter 2 for some examples of these use cases. There are several requirements driving the adoption of accurate timing in the enterprise: Regulatio