a framework for phase and time clocks defined in the ITU T G.8273.x-series. It includes annexes with detailed testing and measurement methods of phase and time clocks. This recommendation includes the following main topic, annexes, and appendixes: General introduction of phase and time clocks that outlines the clock types covered by the G.8273.x set of recommendations Annex A, "Testing and measurement of time/phase clocks" Annex B, "Phase/time clock equipment specification related measurement methods" Several appendixes on aspects of testing clock performance The annexes and appendixes contain details on testing and measurement of phase and time clocks that are worthwhile for studying. There is a correction to this recommendation consented at the October 2020 plenary, but it includes a full reprint of the text, SO only a single document is needed. Link to recommendation: https://handle.itu.int/11.1002/1000/14528 G.8275: Architecture and Requirements for Packet-Based Time and Phase Distribution ITU-T G.8275 describes the architecture and requirements for packet-based time and phase distri- bution in telecom networks using PTP. From the scope of the recommendation: The requirements and architecture form a base for the specification of other functionalities that are needed to achieve packet-based time and phase distribution in a carrier environ- ment. The architecture described covers the case where protocol interaction is at all nodes, between a packet master clock and a packet slave clock or only a subset of the nodes between a packet master clock and a packet slave clock. This scope mentions that every node between a master and a slave clock will be involved in "pro- tocol interaction," which basically means that the nodes are understanding and processing PTP (and not simply switching the packets containing it). This is another way of saying that every node needs to be a boundary clock or a transparent clock. Despite this sentence, if you read section 7 or Ap- pendix I, you'll notice that they cover scenarios whe