Re: [Linuxptp-users] [Linuxptp-devel] Can ptp4l specify master clock source by ip address?

[Maciek M. <ma...@ma...>]

On 6/2/2023 9:01 PM, Trey Harrison wrote:
> Subject kinda says it all.. We have previously been using chrony to
> synchronize systems on a network, and chrony allows slave devices to
> specify the ip address of their clock source.
> 
> It does not seem obvious after reviewing documentation here that this
> is possible:
> 
> https://manpages.ubuntu.com/manpages/bionic/man8/ptp4l.8.html
> 
To achieve this you need to deploy ptp in the unicast mode.

For details - please refer to UNICAST-MASTER.cfg and UNICAST-SLAVE.cfg
in the config subfolder.

And please post usecase-related questions to the linuxptp-users group.


> We generally deploy systems in groups where one is the master clock
> source and the others are started as "slaveOnly" devices. However, it
> is possible that we may have multiple groups like this deployed on the
> same network, where there may be a few sources competing to be the
> "master clock".. but it is important for slaves in one group always
> use their designated master clock, and not any other master clock that
> may also be present on the network.
> 
Do you assign different groups to different domainNumbers?

> We have considered redesigning our systems so that there is only ever
> a single master clock started on the network, with all other nodes
> starting as "slaveOnly".. but that would involve adding further
> configuration options to our software which would be one more thing
> for the system configurators to get wrong when deploying them.
> 
> TLDR; can a 'slaveOnly' ptp4l client specify the ip (ipv4) address of
> the master clock it wants to use?

TLDR; Yes - if you deploy it in unicast mode :)

Thanks,
Maciek

> 
> Thanks!
> 
> Trey
> 
> 
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