[ntp:questions] NTP rootdelay and rootdispersion problem

unruh unruh at invalid.ca
Thu Nov 10 15:55:55 UTC 2011

On 2011-11-10, balaji u <ubalaji83 at gmail.com> wrote:
> my device is connected with a NTP server(stratum 5), which shows round-
> trip delay with its primary reference (stratum 3 server) as 550 to 720
> msec and dispersion as 70 to 160.

That is pretty huge. How is it connecting? pony express? Why are you
using such a bad server? (720ms is enough time for the signal to circle
the earth 5 times. Or I guess if it uses a sattelite as part of the link
it could generate delays like that)

> Whether this could be a problem for my NTP client?. The question

Since ntpd jumps if the time gets out by 128 ms, your delay is getting
to the point where successive timings could have offsets of that order.
And ntpd doing jumps a fair amount of the time is not a good idea. 

> arises because my NTP server is sending packets with its Root delay
> and Root Dispersion values which could create some problem on the NTP
> client side.

Why are you using such a bad server for your server? Buy a gps receiver
and get usec accuracy for your server and then you can stop worrying. 
Or find some better servers to serve your server. 

More information about the questions mailing list