Skip to main content

Network Time Protocols (ntp)

WG Name Network Time Protocols
Acronym ntp
Area Internet Area (int)
State Active
Charter charter-ietf-ntp-04 Approved
Document dependencies
Additional resources Issue tracker, Wiki, Zulip stream
Personnel Chairs Dieter Sibold, Karen O'Donoghue
Area Director Erik Kline
Mailing list Address
To subscribe
Chat Room address

Charter for Working Group

Network Time Protocols working group

Accurate, precise, and reliable time is an important function relied upon by
modern systems, devices, and applications. This requires reliable and accurate
network time synchronization over modern IP-based networks. Additionally,
accurate time is fundamental to implementing many important security
properties, and therefore often must be (cryptographically, or otherwise)
secured. The Network Time Protocols working group is focused on enhancing
existing network time synchronization protocols, such as the Network Time
Protocol (NTP), and specifying new network-time-related protocols or
extensions for purposes that the existing protocols are not well suited to

NTP was first defined in the IETF in RFC 958 in 1985. It has been through
several iterations in the IETF. The latest, NTPv4 (RFC 5905) was published
in 2010. Today, it is a widely used time synchronization protocol
for the synchronization of clocks of various digital systems including
computers, networks, and a myriad of devices. Despite NTP's wide-spread
success, it has become apparent that it needs further development in order
to adequately meet the modern requirements of time synchronization
protocols and to meet the increasing security threats on the Internet.

The working group will continue to address the maintenance of NTPv4,
including extensions and corrections. This includes the introduction of an
interleave mode in order to enhance the accuracy of the network time
synchronization and the introduction of alternative clock selection
algorithms in order to enhance robustness against delay attacks.

NTP remains vulnerable to many types of attacks. Therefore, in 2020, the
working group published Network Time Security (NTS) as RFC 8915. NTS extends
NTP with an authentication approach to ensure authenticity of NTP time
servers and protects the integrity of exchanged NTP packets. The working
group will work on extending NTS to cover the remaining modes of service for
NTP not covered by the initial specification. The working group will also
work on extending NTS for PTP [1] in collaboration with the IEEE 1588
working group.

The working group will also develop an updated version of NTP
(preliminarily known as NTPv5), addressing a number of identified
weaknesses. The new specification will consist of a set of documents,
separating the on-wire protocol engine and the timing engine of NTP
clients and servers. The updated version of NTP will address the security
requirements specified in RFC 7384 and leverage the work completed in
RFC 8915.

Finally, the working group will address other network-time-related
protocols in the IETF (e.g., roughtime) as well as work on items brought to
the group from other standards bodies (e.g. IEEE 1588), with the
acknowledged request to do so from that body.

Working group items:

  • YANG model for NTPv4
  • interleaved mode for NTPv4
  • alternative clock selection algorithms
  • NTS for PTP
  • NTPv5 requirements
  • NTPv5 specification(s)
  • roughtime specification

[1] "IEEE Standard for a Precision Clock Synchronization Protocol for
Networked Measurement and Control Systems," in IEEE Std 1588-2019
(Revision of IEEE Std 1588-2008) , pp.1-499, 16 June 2020,
doi: 10.1109/IEEESTD.2020.9120376.


Date Milestone Associated documents
Dec 2022 NTPv5 requirements
Dec 2022 NTS for PTP
Jun 2022 roughtime core specification
May 2022 NTPv4 YANG data model