[comp.protocols.time.ntp] xntp in broadcast mode.

skl@odin.math.uiuc.edu (Soren Lundsgaard) (03/20/91)

I have one machine called 'o' on our little area of the subnet talking
to ntp-[012].cso.uiuc.edu, running just fine, keeping track of the
time.  I would like it to send the time on to two other machines
called 'a' and 'c' on the same subnet, so I have put a line 'broadcast
128.174.111.255' in ntp.conf, and I have started 'xtnpd -b -f
/etc/ntp.drift' on the other machines.  'a' and 'c' syncronize quite
well to 'o', we are not looking for any great amounts of accuracy on
these machines.  I am using broadcast because it means a fairly short
command line and no ntp.conf file, and because I suspect a number of
other machines in our department will be set up this way.

I have a number of questions about this set up.
Does this sound like a reasonable thing to do?  Should I have two
machines talking to ntp-[012].cso?  Is there any relative gain or loss
in running broadcast versus peer.  What is a reasonable figure for
broadcastdelay in this setup (is the default good)?  Can I ask a
machine at another place on the network to broadcast to my subnet, and
can I broadcast from 'o' to another subnet?  Can I lengthen the
polling interval without a serious loss in accuracy?

I would appreciate hearing from anyone who has experience with using
the broadcast parts of xntp.  I suppose posting would be appropriate
if it is of general interest, otherwise mail to skl@uiuc.edu

skl.