271.1 (FTS), G.8271.2 (PTS) Reference clock G.811 (PRC), G.811.1 G.8272 (PRTC), G.8272.1 (ePRTC) specifications (ePRC) Equipment clock specifica- G.812, G.813, G.8262 G.8262 (EEC), G.8262.1 (eEEC), G.8263, tions for frequency (OEC), G.8262.1 (eOEC) G.8266 (PEC-M) Equipment clock specifica- G.8273.1 (T-GM), G.8273.2 (T-BC/T-TSC), tions for phase/time G.8273.3 (T-TC), G.8273.4 (APTS) Telecom profile for G.8265.1 frequency Telecom profiles for G.8275.1, G.8275.2 phase/time Characteristics of interfaces G.703 However, there is another way to distill this down to a more reasonable subset of recommendations if you are only concerned with using PTP as the timing transport. This distillation makes sense for many readers because it aligns with a use case that only needs a smaller subset of recommendations to implement. Table 8-4 gives a short overview of common use cases and where to get started when deploying a PTP-based solution for either frequency or phase/time. Table 8-4 Commonly Grouped Recommendations for PTP Deployments Network Architecture Architecture Network Limits Clocks Profile Packet frequency G.8265 G.8261.1 G.8263 G.8265.1 Full timing support G.8275 G.8271.1 G.8273.2 G.8275.1 Partial timing support G.8275 G.8271.2 G.8273.4 G.8275.2 Assisted partial timing support G.8275 G.8271.2 G.8273.4 G.8275.2 For example, for an engineer implementing timing for a mobile network, the place to start might be the chosen profile, say G.8275.1. Then the next would be the recommendation for the associated Telecom Boundary Clock (T-BC) and Telecom Time Slave Clock (T-TSC) in G.8273.2. Then, the network architecture associated with that profile (for full on-path timing support) would be the G.8271.1 recommendation for full timing support. Just understanding what is contained in those few recommendations covers most of what the engin- eer would need. Perhaps questions around SyncE or enhanced SyncE might come up, which might bring in G.8262, G.8262.1, and G.8264. Whatever the case, understand that you don't need to con- sult th