Time and Frequency (T&F) services are critical to many civil and industrial sectors, both directly and indirectly, including telecommunications, geo-positioning (autonomous vehicles), energy, finance, and advanced scientific use cases. Access to precise time and frequency signals is,therefore,of major interest to industry, research and the economyworldwide. In the past few years, National Metrology Institutes (NMIs) have successfully developed and tested new T&F techniques using optical fibres which have shown a stability performance of at least three orders of magnitude better than the current best commercial services. Moreover, such techniques offer an alternative to Global Navigation Satellite System (GNSS) for end-users who cannot relyon broadcast signals due to, for example, security concerns such as GPS spoofing attacks or reception issues if they are located in an underground laboratory. Further, new T&F services have the potential to respond effectively to the challenges of tomorrow. Many NRENs are now either supporting T&F services for their users, such as National Metrology Institutes (NMIs), or considering how they might do so. The work of this subtask is documenting existing practices and discussing best future practices. If you are interested in discussing OTFN further with us, please get in touch. | 
