A new Internet-Draft with implementation guidelines on how to handle UTC leap seconds in Internet protocols was posted today on the IETF web site:
"Coordinated Universal Time with Smoothed Leap Seconds (UTC-SLS)", Markus Kuhn, 18-Jan-06. (36752 bytes) http://www.ietf.org/internet-drafts/draft-kuhn-leapsecond-00.txt Background information, FAQ, etc.: http://www.cl.cam.ac.uk/~mgk25/time/utc-sls/ Abstract: Coordinated Universal Time (UTC) is the international standard timescale used in many Internet protocols. UTC features occasional single-second adjustments, known as "leap seconds". These happen at the end of announced UTC days, in the form of either an extra second 23:59:60 or a missing second 23:59:59. Both events need special consideration in UTC-synchronized systems that represent time as a scalar value. This specification defines UTC-SLS, a minor variation of UTC that lacks leap seconds. Instead, UTC-SLS performs an equivalent "smooth" adjustment, during which the rate of the clock temporarily changes by 0.1% for 1000 seconds. UTC-SLS is a drop-in replacement for UTC. UTC-SLS can be generated from the same information as UTC. It can be used with any specification that refers to UTC but lacks provisions for leap seconds. UTC-SLS provides a robust and interoperable way for networked UTC- synchronized clocks to handle leap seconds. By providing UTC-SLS instead of UTC to applications, operating systems can free most application and protocol designers from any need to even know about UTC leap seconds. Please have a careful look at the full specification and rationale. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain