Network Time Protocol Updated for Improved Granularity, IPv6
- By Joab Jackson
Internet Engineering Task Force (IETF) engineers are sharpening the Network
Time Protocol's (NTP's)
granularity of time measurements, as well as making
the veritable time-synchronization standard compatible with version 6 of the
An IETF Internet Draft, "Network Time Protocol Version 4 Protocol and
Algorithms Specification," which was posted
last month, encapsulates the changes.
The NTP Working
Group hopes to submit this draft for consideration as an IETF Request for
Comments (RFC) within the next few weeks, according to working group Cochair
Karen O'Donoghue, lead engineer for the Naval Sea Command's Surface Warfare
Center. O'Donoghue led the working group discussion at the IETF 71st meeting
being held in Philadelphia this week.
Once this update to NTP is published as an RFC, vendors can incorporate the
changes into their own network software and hardware.
NTP is widely used to synchronize clocks across the Internet. Using NTP, local
machines can query regional time servers, which in turn get the Universal Coordinated
Time over the Internet from highly accurate reference clocks. Using algorithms
to estimate the offset caused by transmission times, the current version of
NTP can synchronize local time with a reference clock to within a few hundred
milliseconds, an accuracy that may be maintained by checking the time server
every 1,024 seconds.
This new NTP update includes algorithms that would bring the accuracy to within
tens of milliseconds, and can maintain this accuracy up to 36 hours between
checks with the time server. Such precision has become increasingly necessary
for modern systems.
This draft also includes support for IPv6. It specifies the IPv6 address to
be used for NTP multicast transmissions, as specified by Internet Assigned Numbers
Authority. It also specified changes in the packet headers for IPv6 transmissions.
In addition to this draft, the NTP working group has a few others in the final
stages of being readied for IETF submission. One is on using
encrypting NTP packets through the Public Key Infrastructure. Another details
to use NTP with the Dynamic Host Control Protocol within IPv6. A third details
metrics for monitoring components that use NTP.
The changes in this document will still fall under version 4 of NTP, although
discussions are about to get underway to talk about future versions of the protocol,
O'Donoghue said during the meeting.