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