[ntp:hackers] Mitigation rules
David Mills
mills at udel.edu
Mon Apr 6 17:02:31 UTC 2009
Guys,
NASA/JPL has decided to implement the NTP interleaved modes for Mars
orbiters and deep space missions. These modes are implemented in the
current development verion. This requires some rethink on the mitigation
rules and prefer peer concepts as the intervals between updates can be
significantly longer than the current engineering model. After some
thought I have revised the mitigation rules to support such things as
multiple prefer peers, multiple PPS sources and engineered fallback
should all sources fail. The revised rules are intended to cover the
existing GPS/PPS paradigm, sole PPS source and other more or less
bizarre hookups. The revised rules are at
www.eecis.udel.edu/~mills/ntp/http/prefer.html. They are in fact
implemented in the current development version, which should in almost
all cases be backwards compatible with previous versions..
Dave
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