2.1 KiB
Network Working Group T. Wensing - Individual Contributor
Request for Comments: XXX C. Merten - Individual Contributor
Aug 2019
IPv6 Multicast Time Protocol
This RFC specifies a standard for the ARPA Internet community. Hosts on
IPv6 that choose to implement a Time Protocol are expected
to adopt and implement this standard.
This protocol provides a site-independent, machine readable date and
time. The time service sends back to the originating source the time in
seconds since midnight on January first 1900.
One motivation arises from the fact that not all systems have a
date/time clock, and all are subject to occasional human or machine
error. The use of time-servers makes it possible to quickly confirm or
correct a system's idea of the time, by making a brief poll of several
independent sites on the network.
This protocol may be used either with Link-Local Scope Multicast Addresses or Site-Local Scope Multicast Addresses.
When used via Link-Local Scope Multicast Addresses the time service works as follows:
S: Listen on Multicast Address FF02:0:0:0:0:0:0:37
U: Send empty packet to Multicast Address
S: Send the time as a 32 bit binary coded IPv6 Address.
U: Receive the packet.
U: Close the connection.
S: Close the connection.
The server listens for a connection on Internet Protocol Version 6 Multicast Address FF02:0:0:0:0:0:0:10.
If the server is unable to determine the time at its
site, it should either refuse the connection or close it without
sending anything.
The Time
The time is the number of seconds since 00:00 (midnight) 1 January 1900
GMT, such that the time 1 is 12:00:01 am on 1 January 1900 GMT; this
base will serve until the year 2036.
For example:
the time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT,
2,398,291,200 corresponds to 00:00 1 Jan 1976 GMT,
2,524,521,600 corresponds to 00:00 1 Jan 1980 GMT,
2,629,584,000 corresponds to 00:00 1 May 1983 GMT,
and -1,297,728,000 corresponds to 00:00 17 Nov 1858 GMT