rrying the PTP. See Chapter 9 for more information on the effect of PDV on end-to-end timing performance. SyncE is much quicker to align, more stable (not influenced by traffic load and PDV), and easier to manage and run. SyncE deployment does require the engineer to design loop-free timing paths and manually configure the interfaces to complete the path. Besides support in each intervening node, SyncE also requires every type of transport system to carry frequency accurately and transparently (examples would be microwave or optical). As a rule, the recommendation is to run SyncE wherever you can and PTP wherever you must. Be- cause SyncE and G.8265.1 are designed to easily interoperate, a mixed deployment is quite straight- forward. This allows relatively seamless conversion between TDM, SyncE, and PTP. 11.3 Frequency, Phase, and Time Deployment Options As previously pointed out, all 5G networks, and an increasing number of LTE-A networks, are re- quiring traceable phase and time signals in addition to the existing need for frequency. The follow- ing section of the book covers the various alternatives to delivering accurate frequency, phase, and time to the cell site, with recommendations and best practices. This section concentrates on the main +1.1 us phase alignment to UTC at the point of demarcation to the radio device from the back-haul network. The extra requirements needed in mid-haul and front-haul networks that result from the most recent innovation in the RAN are covered later in the chapter in the section "mid-haul and front-haul Timing". You need to understand the details of the back-haul case before looking to extend this knowledge to the RAN. The major options considered by most MSPs include the following: Install a GNSS receiver as a PRTC everywhere that synchronization is required. Distribute timing signals from a remote PRTC over the back-haul network with full timing sup- port from the network in combination with SyncE. Distribute timing signals from a remote PRTC over the back-haul network wit