Re: [Linuxptp-users] How to properly use twoStepFlag=0

[Keller, J. E <jac...@in...>]

> -----Original Message-----
> From: Timo Korthals [mailto:tko...@ci...]
> Sent: Tuesday, January 15, 2019 12:21 AM
> To: lin...@li...
> Subject: Re: [Linuxptp-users] How to properly use twoStepFlag=0
> 
> >>> To my knowledge there is no off-the-shelf one-step card on the market.
> >>>
> >>> Sorry,
> >>> Richard
> >> Yep, that's as much as I know currently as well.
> >>
> >> Thanks,
> >> Jake
> >>
> > Yea, I read the datasheet section, and it appears that the 1-step insertion doesn't
> update the UDP checksum, so it would definitely not work for the normal UDP frame
> PTP, (as checksums will be invalid).
> But isn't this only important for layer 3 PTP (aka ptp4l -4 and ptp4l -6)?
> Layer 2 PTP (aka ptp4l -2) should work in that case, right?


Yes, that would only impact layer 3 PTP.

However, no working driver has been made to show that it does work, and there's no way for the kernel to indicate that Tx timestamps only work on L2. (As the filtering options are Rx only).

Thanks,
Jake

> >
> > Thanks,
> > Jake
> Greetings,
> Timo
> >
> >
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> --
> 
> Timo Korthals, M.Sc.
> Universität Bielefeld
> AG Kognitronik & Sensorik
> Exzellenzcluster Cognitive Interaction Technology (CITEC)
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> 33619 Bielefeld - Germany
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