[ntp:questions] A few y/n questions about what info I can get from NTP

Erik Corell ecorell at ee.unimelb.edu.au
Thu Jan 20 08:56:51 UTC 2005


Hi, I am doing a research project trying to do clock syncronization
using ntp, pcap and tsc. Hopefully the outcome will be a very accurate
and robust difference clock. I am a little bit stuck at the moment,
having few questions on what ntp can and can not give me.

Please pick one or two or all to answer.

*Is there anyway I can access the final ntp time stamp? (The one my
computer makes when the ntp packet returns)

*Is it possible to know the exact value of the tsc register at the time
for the "originate ts" in the NTP packet? If so is it also possible to
get the exact tsc for when the packet returns?

*Is the there ANY chance ntpd will reset (or step set what ever its
called) my clock after sending but before recieving a NTP packet.

*Is 0.5 ms/sec the most the clock rate may be skewed up or down to
compensate for offset?

*Is the possible to get information about the current clock rate. (Maybe
in terms of tsc.)?

*Can an application using pcap get information about leap seconds from
the NTP packets or is there any other way of letting an application know
when a leap second has occured?

Please, please! It would be great to have answer on at least some of the
question.

Regards,
Erik Corell






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