On Thu, Mar 12, 2009 at 11:06 AM, Tom <[email protected]> wrote: > To All, > > How do you demonstrate the traceability of the NTP solution to BIPM > UTC? >
For "hard" tracability, you really need your own reference clock (typically GPS) that you control, along with several internet based sources as a sanity check against it. If you don't want a reference clock, but want "tracable" time from internet-based sources, you need to use some form of NTP authentication. Typically, this means sharing a "signing" key with at least one (more are better) upstream servers run by organizations that are known to provide good time tracable to UTC. The NTP Autokey protocol was designed to do this without sharing secrets, but is not widely used, and does not work if there is network address translation involved. Is this a regulatory requirement? If so, what nation/regulation are we talking about? Some may require the use of a local reference clock of some type. In the USA, for eample, you may be able to get authenticated time directly from NIST: http://tf.nist.gov/service/auth_ntp.htm -- RPM _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
