[ntp:questions] Re: Synchronization with mobile devices and different time zones
brad at stop.mail-abuse.org
Mon Oct 25 10:17:29 UTC 2004
At 2:50 AM -0700 2004-10-25, Sergio wrote:
> Well, then it's possible. But I assume there is a certain overload
> involved. If a communication takes place once every seventeen minutes
> and that communication is lost (e.g., no network connection
> available), either the clock will not be synchronized until the next
> synchronization point (17 minutes later) or the communication will be
> retried until it is successful, right?
NTP is designed to be used in environments were you occasionally
lose connectivity, packets are dropped, etc.... If it doesn't get a
response this time, then it will try again in the future. This
doesn't normally pose a serious problem unless you lose a lot of
packets over a long period of time.
NTP works pretty hard to always speed up or slow down the clock
and tries to avoid stepping the clock one way or the other. So, if
you've been in operation with good connectivity for a while, then
being disconnected for a time shouldn't hurt too much -- your clock
may drift a bit more than usual, but that should be about as far as
Things get more difficult if your IP address changes, as is more
common for laptops. In that case, you need to either quit and
restart the NTP daemon (perhaps with a configuration file that is
more suitable for your new location), or at least drop all your
current associations and set up new ones (or re-set up the same old
ones, but making the daemon aware of your new IP address).
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
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