PTP as a timing input is useful for several different application scenarios of which one is tunneling time through PTP over the network to the SyncServer with no GNSS connection. PTP input can also be used as a backup time reference in the event of the loss of the GNSS signal. When used as a back up to GNSS, the SyncServer is equipped with Automatic Asymmetry Compensation that automatically measures, calibrates, and stores up to 32 different network path delay asymmetries observed between the PTP slave and the PTP grandmaster. In the event of the loss of the GNSS signal, the slave recognizes the current network path and automatically applies the correct asymmetric path compensation to keep the device tightly synchronized to the remote PTP grandmaster. If the network path between the slave and the grandmaster changes, the applied compensation will also change.