[ntp:questions] Re: NTP and satellite offset

David L. Mills mills at udel.edu
Wed May 4 01:36:48 UTC 2005


Greg,

There is no problem if the clients can synchronized to the server where 
the path to and from the server go via the satellite, as the paths are 
symmetric. I would guess you want to operate in broadcast mode, so that 
two-way communication via the satellite is not possible. You can do that 
with the bdelay and broadcastclient novolley commands at the client. You 
would need something like 270 ms for the delay, which is typical for 
geosynchronoua orbit. If you can stand a short two-way volley, leave off 
the novolley and the setup will calibrate itself.

Where I have had trouble in the past is when the uplink is to a VSAT and 
the return is via a land path. The calibration doesn't work in that 
scenario.

Dave

gsienkiewicz wrote:
> Hello,
> 
> I am trying to implement an NTP server into a satellite network to
> update remote hosts. I am having difficulties accouting for the delay
> in the transfer due to latency on the medium used for communication. I
> am wandering if anyone could suggest an NTPd solution to the problem,
> or a separate NTP server application.
> 
> Thank you,
> 
> Greg Sienkiewicz
> Computer System Technician
> 



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