[ntp:questions] NTP and asymetric delay

Danny Mayer mayer at ntp.isc.org
Sun May 6 03:37:08 UTC 2007

emmanuel.python at bluewin.ch wrote:
> Hello
> I use the version 3 of NTP on cisco routers and I see that if the 
> delay between the NTP server and the client (my cisco router) is not 
> symetrical (like for example 20ms in one direction and 40ms in the 
> other direction) then the time is not very well synchronized on the 
> router => There is an error of 10ms ((40-20)/2). After reading the 
> NTP algorithm, I see that it uses the round trip time to compute the 
> clock offset. So my question is the following: How to configure or 
> use NTP if there are asymetrical delays or jitter?

We don't support NTP v3 any more. If possible upgrade to V4.

This could be done with the fudge command but that currently only
currently supports refclocks. If this is broadcast packets then you
could use broadcastdelay, but I have no idea whether or not any of this
is supported in V3. Is there no possibility of upgrading to V4?

> Thank you for your help
> Emmanuel Python

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