I hadn't run across NIST's leap seconds table before: ftp://time.nist.gov/pub/leap-seconds.list
I'm finally beginning to catch up on NTP developments over the last several years, and find that current xntpd code can use that table, and transport leap second tables around using an "autokey" feature: http://groups.google.com/group/comp.protocols.time.ntp/browse_thread/thread/db2f5f47aab68a3d/ There is an IETF NTP working group now: http://ietf.org/html.charters/ntp-charter.html There was some discussion of leap seconds at the NTP working group session of the Internet Engineering Task Force (IETF) meeting in Vancouver in September: http://www3.ietf.org/proceedings/05nov/ntp.html It is unclear whether the current "autokey" security mechanism will end up in an IETF standard, since it is rather different from other standard internet security mechanisms. That meeting also mentions IEEE 1588-2002 Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems. See http://ieee1588.nist.gov/ It seems that IEEE 1588 time bases are continuous from a defined epoch, but I don't know much more about that. There was also a note in the IETF meeting of possible leap second issues in the RTP protocol. There was later discussion on the NTP working group mail list about sending in comments to the ITU. Here is Steve Allen's comment, cogent as always, and links to the rest: http://lists.ntp.isc.org/pipermail/ntpwg/2005-October/000165.html I don't know if they ever sent in comments to ITU. Neal McBurnett http://bcn.boulder.co.us/~neal/ Signed and/or sealed mail encouraged. GPG/PGP Keyid: 2C9EBA60