ese two different net- work topologies. Finally, G.8275 also examines the different options around the positioning of the sources of time and how to address redundancy concerns. A new version of G.8275 was consented at the October 2020 plenary. Link to recommendation: https://handle.itu.int/11.1002/1000/14509 8.4.1 End-to-End Solution and Network Performance The packet-based timing recommendations covered previously are centered on terms, definitions, requirements, and architecture. These form the basis for this next category, those relating to end-to- end network topology, design, and performance. Because the ITU-T designs a set of recommendations as a total timing solution, one of the first tasks is to define the characteristics of the packet network that will carry the timing. These recommenda- tions also define the performance limits that must be met by the time signal distributed via this net- work. These values are known as the network limits and include the timing error budget for the end-to-end network. The ITU-T covers this for the case of packet networks carrying frequency (G.8261 and G.8261.1) and then for the case of packet networks carrying time and phase (G.8271, G.8271.1, and G.8271.2). The first recommendation in each series covers the general aspects, while the .1 and .2 versions go into the specific limits and error budgets of a specific network topology. G.8271: Time and Phase Synchronization Aspects of Telecommunication Networks ITU-T G.8271 provides the basis for phase and time synchronization. Therefore, it is the equivalent of what G.8261 is to frequency distribution. From the scope of the recommendation: This Recommendation defines time and phase synchronization aspects in telecommunica- tion networks. It specifies the suitable methods to distribute the reference timing signals that can be used to recover the phase synchronization and/or time synchronization according to the required quality. It also specifies the relevant time and phase synchronization interfaces and related performance. 