Network Time Protocol

Network Time Protocol (NTP) synchronizes computer clocks across packet-switched networks. It estimates clock offset and network delay to align local clocks with reference time.

NTP timestamp: A 64-bit NTP time value containing seconds and fractional seconds since 1900. NTP exchanges these timestamps to estimate offset and round-trip delay.
Coordinated Universal Time: The international time standard maintained using atomic clocks and adjusted to remain close to Earth's rotation. NTP implementations commonly distribute time expressed on the UTC timescale.
David L. Mills: An American computer scientist who led the development of NTP and foundational Internet timekeeping work. Mills designed NTP and guided its evolution through successive protocol versions.
NTP pool: A volunteer-run system that distributes requests among publicly available NTP servers. The pool offers a scalable source of time for computers and networked devices.
Precision Time Protocol: A clock-synchronization protocol designed for higher precision, especially on local networks. PTP can achieve finer synchronization than ordinary NTP when hardware support is available.
Clock offset: The difference between a clock's reading and a reference clock's reading. NTP estimates this difference to determine how far a local clock must be corrected.
Unix time: A time representation counting seconds from 1970-01-01 00:00:00 UTC, with system-specific handling of leap seconds. Many NTP clients convert synchronized time into the Unix time used by operating systems.
Internet Engineering Task Force: The standards organization that develops and publishes technical specifications for the Internet. IETF documents define interoperable versions and extensions of NTP.
Chrony: A software implementation of NTP designed to synchronize system clocks across varied network conditions. Chrony is a common alternative client and server implementation for NTP.
Simple Network Time Protocol: A simplified time-synchronization protocol that omits some of NTP's clock-discipline complexity. SNTP clients use NTP-compatible messages but generally provide less robust timekeeping.

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