Re: [Linuxptp-users] Hardware timestamping with bridge device?

[Richard C. <ric...@gm...>]

On Tue, Mar 18, 2014 at 11:48:19AM +0100, Thomas Mayer wrote:
> Hi everybody,
> 
> for a project I have to synchronize around 3 or 4 devices. Because all 
> devices have two ethernet ports, one requirement is not to use a 
> separate network switch. Instead the idea is to chain up all devices and 
> use the middle device(s) as bridge(s).
> 
> Example:
> 
> DEV1_eth0|DEV1_eth1 <--> DEV2_eth0|DEV2_eth1 <--> DEV3_eth0|DEV3_eth1
> 
> I have already tried a few things, but it seems that it's not possible 
> to use hardware timestamping with a bridge device.

You would need to write firewall rules to divert PTP events to the
local host.
 
> Has anybody tried to build something like this and can give me a little 
> help?

So you want to build a Transparent Clock?  Linuxptp does not implement
this, but you might be able to reuse parts of the code. I think it
will be a bit of work.

Good luck,
Richard