[ntp:questions] broadcast/multicast users: ntpq peers vs. lpeers

Dave Hart hart at ntp.org
Thu Oct 20 13:33:15 UTC 2011


If you manage ntpd clients in a broadcast or multicast configuration,
I'm particularly interested in your opinion regarding ntpq's peers and
lpeers commands.

peers, often invoked with "ntpq -p", omits associations which are
neither configured nor reachable.  In this context, configured means
the association resulted directly from a ntp.conf directive such as
"server tock", as opposed to ephemeral and preemptible associations
spun up after initial startup by automatic server discovery schemes
(broad/multicast, manycast, pool).  lpeers, in contrast, includes all
associations.

In my use of manycastclient and it's evil twin, the 4.2.7 overhaul of
pool, I have found the omission unhelpful, and tended to switch to
using "ntpq -c lpeers" (or shorter, "ntpq -clpe") so I can see
recently-added preemptible associations during the first poll
interval, before they become reachable.  This made me curious about
when the peers omission is helpful.  Dr. Mills mentioned to me that
the omission might be appealing to those with ntpd clients in
broadcast or multicast configuration.

I have relatively little experience with NTP broadcast and multicast
nets, particularly with lots of casters.  If you have such a
configuration, please compare peers vs. lpeers against a
broadcast/multicast client.  How would you feel if peers were changed
to always show all associations as lpeers does?

Cheers,
Dave Hart


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