Re: clock synchronization over IP

From	Chris <xxx.syseng.yyy@gfsys.co.uk>
Newsgroups	comp.arch.embedded
Subject	Re: clock synchronization over IP
Date	2018-09-22 00:11 +0100
Organization	Aioe.org NNTP Server
Message-ID	<po3tra$1ckf$1@gioia.aioe.org> (permalink)
References	<d5b24da2-d75b-4557-b4c1-53d587fb87a6@googlegroups.com> <po2tii$1lgu$1@gioia.aioe.org> <fomaqd9uai7u7glmt9tvikd0evf6vch3qk@4ax.com> <po3o7a$1453$1@gioia.aioe.org> <3da4bee1-892e-4acb-8077-29200d14da21@googlegroups.com>

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On 09/21/18 23:16, gp.kiwi@gmail.com wrote:

>
> Thanks for all the replies.  I really appreciate all the suggestions and the level of expertise here.
>
> The software is running on embedded Linux and every node will have a Moxa switch because we need redundant paths.

If NTP "favours" a packet with the shortest round trip time then that 
should work fairly well.
>
> The micro is an ARM9 LPC3250. I'm curious to know something.  When an NTP packet arrives somewhere, is the NTP

processing and response all done in the ethernet chip without the need 
for the operating system to switch

threads to process the message.

Don't want to appear rude, but if you have to ask questions like that,
perhaps you need some engineers on the project who know what they are
doing ?. But yes, multiple levels of the stack may have to be traversed
to get the ntp stuff processed, including the ntp client daemon. Also, 
embedded Linux may or may not be suitable, as it was never
designed for hard real time work of that type and may have significant
latency, though there may be versions optimised in some way.

>
> We also need to synchronize time between the ARM micro and a K64 micro running MQX that is on the same board.

The ARM micro will be the master.  Any ideas for the best way to get the 
synch time from the ARM to the K64?
>

Sounds really complex, so what is this project trying to do overall ?...

Chris

Thread

clock  synchronization over IP gp.kiwi@gmail.com - 2018-08-24 17:54 -0700
  Re: clock  synchronization over IP Paul Rubin <no.email@nospam.invalid> - 2018-08-24 18:28 -0700
  Re: clock  synchronization over IP wzab01@gmail.com - 2018-09-15 09:00 -0700
    Re: clock  synchronization over IP gp.kiwi@gmail.com - 2018-09-15 15:08 -0700
      Re: clock  synchronization over IP George Neuner <gneuner2@comcast.net> - 2018-09-16 08:49 -0400
        Re: clock  synchronization over IP gp.kiwi@gmail.com - 2018-09-17 01:45 -0700
          Re: clock  synchronization over IP George Neuner <gneuner2@comcast.net> - 2018-09-17 11:30 -0400
            Re: clock  synchronization over IP gp.kiwi@gmail.com - 2018-09-17 15:04 -0700
              Re: clock  synchronization over IP George Neuner <gneuner2@comcast.net> - 2018-09-17 22:10 -0400
                Re: clock  synchronization over IP graeme.prentice@gmail.com - 2018-09-18 04:23 -0700
                Re: clock  synchronization over IP Andrew Smallshaw <andrews@sdf.org> - 2018-09-18 13:19 +0000
                Re: clock  synchronization over IP Mikko OH2HVJ <mikko.syrjalahti@nospam.fi> - 2018-09-19 18:56 +0300
                Re: clock  synchronization over IP upsidedown@downunder.com - 2018-09-22 11:51 +0300
          Re: clock synchronization over IP Clifford Heath <no.spam@please.net> - 2018-09-18 21:10 +1000
  Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-21 15:00 +0100
    Re: clock  synchronization over IP Dimiter_Popoff <dp@tgi-sci.com> - 2018-09-21 17:12 +0300
      Re: clock  synchronization over IP Robert Wessel <robertwessel2@yahoo.com> - 2018-09-21 09:58 -0500
        Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-21 16:26 +0100
      Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-21 16:02 +0100
    Re: clock  synchronization over IP George Neuner <gneuner2@comcast.net> - 2018-09-21 17:15 -0400
      Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-21 22:35 +0100
        Re: clock  synchronization over IP "gp.kiwi@gmail.com" <graeme.prentice@gmail.com> - 2018-09-21 15:16 -0700
          Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-22 00:11 +0100
            Re: clock  synchronization over IP "gp.kiwi" <graeme.prentice@gmail.com> - 2018-09-21 16:35 -0700
              Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-22 14:19 +0100
              Re: clock  synchronization over IP gnuarm.deletethisbit@gmail.com - 2018-09-22 07:22 -0700
            Re: clock  synchronization over IP graeme.prentice@gmail.com - 2018-09-21 19:40 -0700
        Re: clock  synchronization over IP George Neuner <gneuner2@comcast.net> - 2018-09-21 22:17 -0400
          Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-22 13:58 +0100
          Re: clock synchronization over IP Brett <ggtgp@yahoo.com> - 2018-09-22 18:50 +0000
    Re: clock  synchronization over IP upsidedown@downunder.com - 2018-09-22 11:56 +0300
      Re: clock  synchronization over IP gnuarm.deletethisbit@gmail.com - 2018-09-22 07:31 -0700
        Re: clock  synchronization over IP upsidedown@downunder.com - 2018-09-22 20:02 +0300
          Re: clock  synchronization over IP gnuarm.deletethisbit@gmail.com - 2018-09-22 14:40 -0700
    Re: clock  synchronization over IP gnuarm.deletethisbit@gmail.com - 2018-09-22 07:06 -0700
    Re: clock  synchronization over IP Mikko OH2HVJ <mikko.syrjalahti@nospam.fi> - 2018-09-22 20:16 +0300
      Re: clock  synchronization over IP Chris <xxx.syseng.yyy@gfsys.co.uk> - 2018-09-22 22:22 +0100

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