Network Time Protocol

E42445

network protocol time synchronization protocol

Network Time Protocol (NTP) is a widely used networking protocol designed to synchronize the clocks of computers and devices over packet-switched, variable-latency data networks.

Try in SPARQL Jump to: Surface forms Disambiguation Statements Elicitation Referenced by

All labels observed (14)

Label	Occurrences
Network Time Protocol canonical	10
NTP	5
NTPv3	2
NTPv4	2
Network Time Protocol Version 4: Protocol and Algorithms Specification	2
NTP reference implementation	1
NTP timestamp format	1
NTPv1	1
NTPv2	1
NTS for NTP	1
Network Time Protocol (Version 3) Specification, Implementation and Analysis	1
Network Time Protocol Working Group	1
Network Time Protocol version 3	1
Simple Network Time Protocol	1

How this entity was disambiguated

This entity first appeared as the object of triple T322236 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.

NED1 Entity disambiguation (via context triple) gpt-5-mini-2025-08-07

Target entity: Network Time Protocol
Context triple: [PTP, competesWith, Network Time Protocol]

A. IEEE 1588 Precision Time Protocol standard
The IEEE 1588 Precision Time Protocol standard defines a method for highly accurate time synchronization over packet-based networks, widely used in industrial automation, telecommunications, and power systems.
B. IEEE 802.1AS timing and synchronization standard
The IEEE 802.1AS timing and synchronization standard defines precise time synchronization mechanisms for time-sensitive networking over Ethernet, enabling coordinated, low-latency communication in applications such as industrial automation and audio/video transport.
C. International Atomic Time
International Atomic Time is a high-precision time standard based on the combined output of atomic clocks worldwide, serving as the fundamental reference for modern civil and scientific timekeeping.
D. Internet Protocol
Internet Protocol is the core networking protocol that defines how data packets are addressed and routed across interconnected computer networks, forming the foundation of the modern internet.
E. Coordinated Universal Time
Coordinated Universal Time (UTC) is the primary global time standard by which the world regulates clocks and time, serving as the basis for most civil time zones.
F. None of above. chosen
G. Unsure - the case is ambiguous/there is not enough information to decide.

NED2 Entity disambiguation (via description) gpt-5-mini-2025-08-07

Target entity: Network Time Protocol
Target entity description: Network Time Protocol (NTP) is a widely used networking protocol designed to synchronize the clocks of computers and devices over packet-switched, variable-latency data networks.

A. IEEE 1588 Precision Time Protocol standard
The IEEE 1588 Precision Time Protocol standard defines a method for highly accurate time synchronization over packet-based networks, widely used in industrial automation, telecommunications, and power systems.
B. IEEE 802.1AS timing and synchronization standard
The IEEE 802.1AS timing and synchronization standard defines precise time synchronization mechanisms for time-sensitive networking over Ethernet, enabling coordinated, low-latency communication in applications such as industrial automation and audio/video transport.
C. International Atomic Time
International Atomic Time is a high-precision time standard based on the combined output of atomic clocks worldwide, serving as the fundamental reference for modern civil and scientific timekeeping.
D. Internet Protocol
Internet Protocol is the core networking protocol that defines how data packets are addressed and routed across interconnected computer networks, forming the foundation of the modern internet.
E. Coordinated Universal Time
Coordinated Universal Time (UTC) is the primary global time standard by which the world regulates clocks and time, serving as the basis for most civil time zones.
F. None of above. chosen

Statements (55)

Predicate	Object
instanceOf	network protocol ⓘ time synchronization protocol ⓘ
abbreviation	NTP ⓘ
canUse	GPS receivers as reference clocks ⓘ atomic clocks as reference clocks ⓘ radio clocks as reference clocks ⓘ
currentVersion	NTPv4 ⓘ linked to: Network Time Protocol
defaultPort	123/UDP ⓘ
definedIn	RFC 5905 ⓘ
defines	stratum 0 reference clocks ⓘ stratum 1 primary time servers ⓘ stratum 2 secondary time servers ⓘ
designedBy	David L. Mills ⓘ
epoch	1900-01-01 00:00:00 UTC ⓘ
firstSpecified	1985 ⓘ
handles	variable-latency data networks ⓘ
hasAlternative	Precision Time Protocol ⓘ linked to: IEEE 1588 Precision Time Protocol standard Simple Network Time Protocol ⓘ linked to: Network Time Protocol
isUsedBy	embedded systems ⓘ network infrastructure devices ⓘ operating systems ⓘ servers ⓘ
layer	application layer ⓘ
messageMode	broadcast ⓘ client-server ⓘ manycast ⓘ multicast ⓘ symmetric active ⓘ symmetric passive ⓘ
operatesOn	packet-switched networks ⓘ
previouslyDefinedIn	RFC 1305 ⓘ
purpose	synchronize clocks of computers and devices ⓘ
securityExtension	NTP Autokey ⓘ NTS for NTP ⓘ linked to: Network Time Protocol
standardizedBy	IETF ⓘ linked to: Internet Engineering Task Force
supports	time synchronization over local area networks ⓘ time synchronization over the Internet ⓘ
timeRepresentation	64-bit timestamp ⓘ
timeSource	UTC ⓘ
timestampFormat	32 bits seconds and 32 bits fractional seconds ⓘ
typicalAccuracy	better than one millisecond on local area networks ⓘ within a few milliseconds over the public Internet ⓘ
uses	Marzullo's algorithm ⓘ User Datagram Protocol ⓘ linked to: UDP clock discipline algorithms ⓘ clock filtering algorithms ⓘ clock selection algorithms ⓘ hierarchical system of time sources ⓘ offset calculation between client and server ⓘ round-trip delay measurement ⓘ stratum model ⓘ
version	NTPv1 ⓘ linked to: Network Time Protocol NTPv2 ⓘ linked to: Network Time Protocol NTPv3 ⓘ linked to: Network Time Protocol NTPv4 ⓘ linked to: Network Time Protocol

How these facts were elicited

Referenced by (30)

Full triples — surface form annotated when it differs from this entity's canonical label.

PTP → competesWith → Network Time Protocol ⓘ

PTP → isMorePreciseThan → Network Time Protocol ⓘ

Cisco IOS → supportsProtocol → NTP ⓘ