Challenges in Time Transfer using the Network Time Protocol (NTP)
02 February 2017
Successful time transfer between a network time protocol (NTP) server and client relies on symmetric network delays and accurate, well-behaved NTP servers. NTP network delays and stratum 1 server performance were monitored for several years from multiple clients located in the U.S. Several patterns of asymmetric delay and loss were identified, some pathological. Significant time offsets and other errors were seen in a few NTP stratum 1 servers including some hosted by national agencies. IoT implications are briefly discussed.