Precision timing plays a critical role in the synchronization of telecommunications networks. It enables service providers to use available spectrum resources more efficiently, increase bandwidth and deliver high-speed wireless services. Until now, service providers have used timing sources based on the Global Navigation Satellite System (GNSS) or Global Positioning System (GPS) to provide frequency and time/phase synchronization; but this is changing. Some of the drivers for change relate to impediments associated with GNSS/GPS itself. As well, the sheer growth of wireless network sites required for 5G will make alternate sources of primary or secondary backup timing necessary to keep site costs down and ensure high availability.