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Switch PTPd in One-Step mode

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Rostislav
2015-08-11
2016-03-02
  • Rostislav

    Rostislav - 2015-08-11

    How can I switch ptpd v.2.3.0 in One-Step mode without SNMP. I don't find any information in ptpd help.

     
  • Jan Breuer

    Jan Breuer - 2015-08-18

    There are 3 situations:

    • master mode - it is not possible without hardware assistance - not implemented in PTPd
    • slave in E2E - it will use one-step and two-step messages without any configuration
    • slave in P2P - it can use messages in one-step mode but it will generate two step "PDelayResp"/"PDelayRespFollowUp"

    In general - ptpd is able to process one-step and two-step messages correctly but it is not possible to generate one-step messages.

     
    • Rostislav

      Rostislav - 2015-08-19

      Hello,thank you for help!

      We have got a one more question.
      PTPd (master mode) send three messages SINC, DELAY_RESPONSE and FOLLOW_UP.
      Can we disable in PTPd the sending of FOLLOW_UP message ?

      Best regards,
      Rostisalv

       
  • Rostislav

    Rostislav - 2015-08-21

    Hello.

    In SYNC Message there is field of flags, one of this flags TwoStep flag, this flag we can change by SNMP. Whether there are other software ways to change the flag ?

    Best regards,
    Rostisalv

     

    Last edit: Rostislav 2015-08-21
  • Jan Breuer

    Jan Breuer - 2015-08-21

    Hello,
    I understand what you want but no, there is currently no souch feature. We can introduce some switch but with big warning:

    Without hardware assistance, it is not possible to make "one step" precise. PTPd fills output timestamp with some estimate, but it is NOT real output timestamp. You will loose some precision and introduce undefined varying assimetry between uplink and downlink depending on the NIC, kernel driver, machine speed etc.

    JB

     
  • Rostislav

    Rostislav - 2015-08-24

    Hello, thank you for answer.

    We can put timestamp to any PTP message, and change by hardware OneStep/TwoStep bit. But we can't change by hardware number of messages. Can we change number of PTP messages with the help of the PTP daemon ?

    Best regards,
    Rostisalv

     

    Last edit: Rostislav 2015-08-25
  • Wojciech Owczarek

    Hi,

    You are free to make any modifications you need for your project, but for ptpd it makes no sense to make any provisions for one-step masters if we don't even have a working generic hardware integration mechanism yet.

    What do you mean by number of messages - sequence number or message rate? Or sending the follow-up?

    Regards,
    Wojciech

     

    Last edit: Wojciech Owczarek 2015-08-25
    • Rostislav

      Rostislav - 2015-08-26

      Hello, thank you for answer.

      I meen enable/disable sending follow-up message.

      Best regards,
      Rostislav

       
  • Wojciech Owczarek

    To be honest it's not really that hard to find it, it's all in protocol.c...

    You would expect that follow-up is sent after receiving our own Sync message, right?

    Just start with processMessage(). Two functions deeper you will see issueFollowUp() being called.

    Regards,
    Wojciech

     
    • Rostislav

      Rostislav - 2015-08-26

      Thank you, it's realy helpful.

      Yes, right, we try to make a OneStep mode in PTP daemon. By default PTPd send two or three mesages, sync, delay response and follow up. For OneStep mode I need to disable Follow Up meassage.

       
      • Mirek Sobczak

        Mirek Sobczak - 2016-03-01

        Hello Rostislav

        Have you succeed with OneStep mode in PTPd?

        Regards
        Mirek

         
        • Wojciech Owczarek

          Mirek,

          PTPd will support one-step and two-step as slave with no issues, but if you want one-step as master, it is impossible without hardware support. Your hardware has to specifically support one-step mode and not that many NICs actually do. There is a hardware-enabled port of ptpd I'm developing: https://github.com/wowczarek/ptpd/tree/wowczarek-2.3.2-hwtest - but I haven't included one-step support, given that I have no hardware available that supports it.

          We could add a one-step mode setting for master operation, but it is pointless without hardware support.

          Regards,
          Wojciech

           

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