Hi Patrick,

the time received by ptp4l is wobbling. This could just be the effect of a 
network switch that is not a transparent clock and thereby delays some PTP 
packets more than others. You can try to connect the master and the slave 
directly to see if this problem goes away.

Cheers,
Axel

> On Jul 22, 2020, at 1:13 AM, Patrick Nowak <patrick.no...@nordsys.de> wrote:
> 
> Hello,
>  
> we are currently evaluating the usage of the Greyware Domain II Time software 
> server as a GM in our small local network. We have a seperate LAN with four 
> nodes. One machine is running Windows and should act as a GM, getting time 
> from NTP and serving the time via PTP. The other three nodes run linuxptp 
> with the standard configuration. All nodes use NICs with IEEE 1588 support.
>  
> The ptp4l on all nodes currently shows a frequently jumping master offset and 
> frequency. Sometimes a message like „running in a temporal vortex" appears. 
> An example from the syslog for the jumping values:
>  
> Jul 22 10:02:50 machine1 ptp4l: [1691104.796] [0:eno1] master offset     
> -91671 s2 freq  -57292 path delay    185856
> Jul 22 10:02:51 machine1 ptp4l: [1691105.695] [0:eno1] master offset     
> -43204 s2 freq  -36326 path delay    168982
> Jul 22 10:02:52 machine1 ptp4l: [1691106.596] [0:eno1] master offset      
> 54956 s2 freq  +48873 path delay    168982
> Jul 22 10:02:53 machine1 ptp4l: [1691107.496] [0:eno1] master offset     
> -42141 s2 freq  -31737 path delay    168982
> Jul 22 10:02:54 machine1 ptp4l: [1691108.396] [0:eno1] master offset     
> 120684 s2 freq +118445 path delay    168982
> Jul 22 10:02:55 machine1 ptp4l: [1691109.296] [0:eno1] master offset    
> -181193 s2 freq -147226 path delay    168982
> Jul 22 10:02:56 machine1 ptp4l: [1691110.196] [0:eno1] master offset      
> 47053 s2 freq  +26662 path delay    168982
> Jul 22 10:02:57 machine1 ptp4l: [1691111.096] [0:eno1] master offset      
> 35055 s2 freq  +28780 path delay    168982
> Jul 22 10:02:57 machine1 ptp4l: [1691111.996] [0:eno1] master offset      
> 80957 s2 freq  +85198 path delay    168982
> Jul 22 10:02:58 machine1 ptp4l: [1691112.896] [0:eno1] master offset     
> -73222 s2 freq  -44694 path delay    168982
> Jul 22 10:02:59 machine1 ptp4l: [1691113.797] [0:eno1] master offset     
> -35597 s2 freq  -29035 path delay    168982
>  
> It seems that the nodes are communicating the network. I’ve also added a PCAP 
> file of the PTP traffic.
>  
> I am currently not really sure whats going on here or what to look for. Does 
> anybody with a little bit more knowledge of PTP/IEEE 1588 have any ideas as 
> to what I could further debug or change in either configurations?
>  
> Best regards,
> Patrick
>  
>  
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