RE: [ocpp] [OASIS Issue Tracker] (OCPP-15) Write Change Request: Time improvements

[Brendan McMahon <Brendan.McMahon@esb.ie>]

Hi Ali, (All),

Based on some quick tests on a typical (Linux based) system using the common "ntpdate" NTP client, with a default NTP client configuration, the network traffic for one synchronization round is four sets of round trips to the NTP server, with each UDP NTP message being exactly 90 bytes (in each direction) (i.e. 720 bytes total).

However, the three subsequent rounds are really only fine tuning the time in the millisecond range by estimating/adjusting for average network latency.

By changing the invocation parameters to a single round of "samples" ( "-p 1"), the total traffic is 180 bytes, but the time could be off by few seconds if a network congestion affected the packets flowing either way. 

Two rounds (360 bytes) might be a reasonable compromise if bytes are relatively expensive and accuracy to "within a second" is desired.

 

Best Regards, 

Brendan McMahon | Systems Architect | ESB ecars | T: +353 1 702 6708 / +353 87 662 2150 | www.esb.ie 




-----Original Message-----
From: ocpp@lists.oasis-open.org [mailto:ocpp@lists.oasis-open.org] On Behalf Of OASIS Issues Tracker
Sent: 16 November 2016 16:32
To: ocpp@lists.oasis-open.org
Subject: [ocpp] [OASIS Issue Tracker] (OCPP-15) Write Change Request: Time improvements


    [ https://issues.oasis-open.org/browse/OCPP-15?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=64339#comment-64339 ] 

Ali Imran commented on OCPP-15:
-------------------------------

Does anyone know how much of the data would be consumed by NTP. Just in case the data prices are higher in some places.


> Write Change Request: Time improvements
> ----------------------------------------
>
>                 Key: OCPP-15
>                 URL: https://issues.oasis-open.org/browse/OCPP-15
>             Project: OASIS OCPP Electric Vehicle Charging Equipment Data Exchange TC
>          Issue Type: Task
>         Environment: 2.0 RC 2 (old version) improvements
>            Reporter: Jonel Timbergen
>            Assignee: Robert de Leeuw
>            Priority: Trivial
>
> Write CR for Time improvements (based on old 2.0RC and input from 
> others/other sources) and submit to TC



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