[ntp:questions] Client doesn't drop failed source
Richard B. Gilbert
rgilbert88 at comcast.net
Sat Jan 9 02:48:15 UTC 2010
Michael Moroney wrote:
> David Woolley <david at ex.djwhome.demon.invalid> writes:
>
>> Michael Moroney wrote:
>
>>> that synchronizes with the four clocks, and ntpq> peers shows one of the
>>> primaries with a "*" in the first column meaning it was synchronized to as
>>> time source, the other 3 show "+" as expected, meaning they are usable
>>> sources. We disconnect the antenna of the selected clock. As expected
>
>> * and + mean they are used, not just that they are usable. The time
>> used to discipline the clock is a weighted average of all of them.
>
> If it uses all of them, what is the difference between "*" and "+"?
> It still doesn't explain why the disconnected clock doesn't get dropped.
>
"*" designates the primary source of time. "+" designates an "advisory"
source. It's available for use if something happens to the primary
source.
See Dave Mills' book on NTP, and RFC-1305. RFC-1305 is for V3 of NTP.
There's an RFC in preparation for V4 but as of the last time I heard it
was being written by a committee and may be released sometime in the
next decade!
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