On Feb 17, 2014, at 12:14 AM, Hal Murray <[email protected]> wrote: > [email protected] said: >> Sure. ~10 per minute is the highest rate a normal client using iburst will >> startup as; after that one packet per minute (every 64 seconds, actually) is >> the most rapid polling rate that should be used without prior coordination. > > If you are thinking about this area, it's important to note that 10 per > minute is different from 1 per 6 seconds. iburst sends a batch of 6 packets > at 2 second intervals.
Indeed yes. Per-second rate limits don't match up well for NTP traffic, since a reasonable rate even for a burst is under 1 PPS. > How do packet filters compute average packet rate? (I'll have to go look at > the code to see how ntpd does it.) The code I've written keeps timers at second, minute, and hour granularity. :-) Stuff like iptables, pf, etc tend to either do similar, or they let you say "limit of X packets per N second window", and admins then typically configure a 5-second window to permit a burst and a 60- or 120-second window for longer-term rates. Regards, -- -Chuck _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
