In one embodiment, a clock on a network device is initialized, and then a first timing message is received at the network device from a reference device having a first timestamp indicating when the first timing message was transmitted from the reference device. The network device may then determine and store a one-way delay from the first timestamp to a first time at which the first timing message was received at the network device. In response to restarting the clock, the network device may receive a second timing message from the reference device having a second timestamp indicating when the second timing message was transmitted from the reference device. The network device may then calibrate the clock such that a second time at which the network device received the second timing message is the second timestamp plus the stored one-way delay.