The Network Time Protocol (NTP), conceived by Professor D.L. Mills at the University of Delaware in 1985, is a pivotal technology for high-precision computer time synchronization over networks. It not only estimates packet round-trip delays but also independently assesses computer clock deviations. NTP operates on a hierarchical system where top-tier servers (level one) directly synchronize with national standard time. Second-tier servers achieve synchronization indirectly via the first-tier servers. Each server in this hierarchy maintains its clock to a specific accuracy level and periodically sends time synchronization requests to a server in the tier above.

For robustness in time synchronization, it's recommended to have more than three synchronization paths. Each path's clock filter selects the optimal value from recent clock deviations. The clock selector then evaluates the synchronization costs of each path, primarily based on packet round-trip time delays. Paths with longer delays incur higher costs. The system prefers clock deviations from lower-cost paths for synchronization. The clock combiner subsequently aggregates these deviations, applying them through a phase-locked loop to adjust the NTP server's own clock.

The website http://www.eecis.udel.edu/~ntp is a prominent online resource for NTP, offering complimentary access to NTP server software, a wealth of technical documentation, information on public time synchronization sites, and client time synchronization software.

Furthermore, in late 1996, we established our NTP server (as outlined in RFC 1305) and began providing time synchronization services from May 1987. To accommodate the increasing user base, the current server address used is

• tock.stdtime.gov.tw
• watch.stdtime.gov.tw
• time.stdtime.gov.tw
• clock.stdtime.gov.tw
• tick.stdtime.gov.tw