des the following main topic and appendixes: Network limits at the various points in the network from A through E Appendix I, "Clock models for noise accumulation simulations" (noise accumulation models for T-BC and T-TC) Appendix II, "Hypothetical reference models used to derive the network limits" Appendix III, "Network limit considerations" (how to measure the network limits in the embed- ded slave case) Appendix V, "Example of design options" (includes TE budgeting and failure scenarios) Appendix VII, "Maximum relative time error" (covers the difference between absolute time er- ror and relative time error, with Figure VII.1 demonstrating the difference; a very important concept for engineers deploying time in the front-haul) Appendixes VIII, "Models for budgeting in a chain of microwave devices" Appendix IX, "Models for budgeting in a chain of xPON or xDSL devices" Appendix XII, "Examples of design options for front-haul and clusters of base stations" G.8271.1 is one of the most important of the recommendations, because it defines the behavior of the end-to-end network that is used to transport the packet-based synchronization. This is the "best in class" model for deployment of packet-based transport of time. It includes a wealth of detailed information on the more detailed design decisions for a timing synchronization network. Two versions of this recommendation were consented in 2020, with both being a complete reprint. Link to recommendation: https://handle.itu.int/11.1002/1000/14527 G.8271.2: Network Limits for Time Synchronization in Packet Networks with Partial Timing Support for the Network ITU-T G.8271.2 specifies the network limits for time and phase synchronization in packet networks with partial timing support from the network (or "without full on-path support"). This case of partial on-path support is directly equivalent to the G.8271.1 recommendation that covers the case with full on-path support. This recommendation covers two use cases with partial support: Assisted partial timing support (AP