[time-nuts] wifi with time sync
shouldbeq931 at gmail.com
Fri Jan 13 19:11:49 EST 2017
On Fri, Jan 13, 2017 at 8:45 PM, Chris Albertson
<albertson.chris at gmail.com> wrote:
> Short answer: See man page for ntpq
> First run NTP then after some time (15 minute to an hour) at the command
> line time type "ntpq -p"
> "ntpq" will query NTP for timing statistics. It will report the average
> delay between the local computer and the set of reference clocks (other
> servers) that NTP is connected to. Along with the average delay you get
> variation in that delay (std dev?) Note the if NTP can calculate the
> delay, it has already compensated for it. It is only the uncertainty of
> the compensation that matters, hence the need to report the variation.
> The data shows the total delay and variation over the network and the
> reference clocks might be thousands of miles away. So you might want to
> run one on say your wifi router or a local computer with hardwire
> connection to the router then you'd see the effect of only your wifi.
> On Fri, Jan 13, 2017 at 12:35 PM, Bob Camp <kb8tq at n1k.org> wrote:
>> What standard protocol would you recommend I run from the command line on
>> my computer
>> to get a quick estimate of the timing lag and variablilty on my
>> particular WiFi connection?
>> > On Jan 13, 2017, at 3:25 PM, John Hawkinson <jhawk at MIT.EDU> wrote:
>> > Can we please stop talking about pings?
>> > Bob Camp <kb8tq at n1k.org> wrote on Fri, 13 Jan 2017
>> > at 15:12:38 -0500 in <C88C78A6-A015-4DCC-9E23-394DC33A3470 at n1k.org>:
>> >> I’m sure you are right about the response time. Right now the
>> >> variation is running almost 3 ms at one sigma on a ping so there is
>> >> a lot to do simply to get the accuracy anywhere near 1 us.
Presuming that the computer on the WiFi network is a supported Unix, I
might use PTP to measure one way delay, PTP needs "special" hardware
to do hardware timestamping, but _can_ be run on any network
I'd guess that the the WiFi for doing "sub microsecond" accuracy would
not be the current 2.4ghz and 5ghz, but 802.11ay
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