Good morning all,

I am setting up a gsm unit with either a pool.ntp.org time server or a time=
..apple.com. I understand that the ntp has a complex algorithm for time sync=
ing, but I was wondering if there was an ballmark sync interval to the serv=
er. Will the time server sync occur at least once a month? or more than onc=
e in 6 months? And does anyone know if a time server connection will consum=
e gprs data? I ask because sim cards expire without any use (6 months) and =
I'm left wondering if NTP time server syncs will consume a noticeable enoug=
h amount of cellular data to keep the SIM card from being cancelled?

Thank you and have a nice day,

Gualtiero

On 2016-11-02, Gualtiero <cerespowerdisystemgsm@gmail.com> wrote:
> Good morning all,
>
> I am setting up a gsm unit with either a pool.ntp.org time server or a time.apple.com. I understand that the ntp has a complex algorithm for time syncing, but I was wondering if there was an ballmark sync interval to the server. Will the time server sync occur at least once a month? or more than once in 6 months? And does anyone know if a time server connection will consume gprs data? I ask because sim cards expire without any use (6 months) and I'm left wondering if NTP time server syncs will consume a noticeable enough amount of cellular data to keep the SIM card from being cancelled?
 
 By default the max time interval is 2^10 sec ( about 20 min) between
 packets sent out and received. That is if the time on your system is
 very well behaved. It sends out a packet and receives a packet of about
 64 bytes. It of course has to be connected to the net, and ntp has no
 idea about net connection, or if the net is up or not. Thus, if your
 system connects when there is data to send, that could severely mess up
 the timing, and it would drop to about one packet a minute. 
 Whetehr or not ntp traffic is enough to make the service provider think
 that there is traffic on the network-- you would have to ask them.

>
> Thank you and have a nice day,
>
> Gualtiero

On Wednesday, November 2, 2016 at 10:58:13 AM UTC, William Unruh wrote:
> On 2016-11-02, Gualtiero wrote:
> > Good morning all,
> >
> > I am setting up a gsm unit with either a pool.ntp.org time server or a =
time.apple.com. I understand that the ntp has a complex algorithm for time =
syncing, but I was wondering if there was an ballmark sync interval to the =
server. Will the time server sync occur at least once a month? or more than=
 once in 6 months? And does anyone know if a time server connection will co=
nsume gprs data? I ask because sim cards expire without any use (6 months) =
and I'm left wondering if NTP time server syncs will consume a noticeable e=
nough amount of cellular data to keep the SIM card from being cancelled?
> =20
>  By default the max time interval is 2^10 sec ( about 20 min) between
>  packets sent out and received. That is if the time on your system is
>  very well behaved. It sends out a packet and receives a packet of about
>  64 bytes. It of course has to be connected to the net, and ntp has no
>  idea about net connection, or if the net is up or not. Thus, if your
>  system connects when there is data to send, that could severely mess up
>  the timing, and it would drop to about one packet a minute.=20
>  Whetehr or not ntp traffic is enough to make the service provider think
>  that there is traffic on the network-- you would have to ask them.
> >


Thank you William! Have a nice day.

Gualtiero wrote:
> I am setting up a gsm unit with either a pool.ntp.org time server or a time..apple.com. I understand that the ntp has a complex algorithm for time syncing, but I was wondering if there was an ballmark sync interval to the server. Will the time server
sync occur at least once a month? or more than once in 6 months? And does anyone know if a time server connection will consume gprs data? I ask because sim cards expire without any use (6 months) and I'm left wondering if NTP time server syncs will
consume a noticeable enough amount of cellular data to keep the SIM card from being cancelled?

FYI: <https://www.eecis.udel.edu/~mills/ntp/html/warp.html>
 <https://www.eecis.udel.edu/~mills/ntp/html/poll.html>

<http://www.ftmc.lt/lt/struktura/skyriai/metrologijos-skyrius/laiko-ir-daznio-etalono-laboratorija/IEEEFCjointEFTF2011.pdf>
<http://pages.cs.wisc.edu/~rkrish/papers/IMC-2016.pdf>
<http://dl.ifip.org/db/conf/ifip6-8/pwc2007/KovarM07.pdf>


-- 
E-Mail Sent to this address <BlackList@Anitech-Systems.com>
  will be added to the BlackLists.

On 07/11/16 22:02, E-Mail Sent to this address will be added to the 
BlackLists wrote:
> Gualtiero wrote:
>> I am setting up a gsm unit with either a pool.ntp.org time server or a time..apple.com. I understand that the ntp has a complex algorithm for time syncing, but I was wondering if there was an ballmark sync interval to the server. Will the time server
> sync occur at least once a month? or more than once in 6 months? And does anyone know if a time server connection will consume gprs data? I ask because sim cards expire without any use (6 months) and I'm left wondering if NTP time server syncs will
> consume a noticeable enough amount of cellular data to keep the SIM card from being cancelled?
>

Syncs happen once every 16 seconds to 20 minutes.  If you are syncing on 
periods of days, there is no point in using the full NTP protocol, and 
if you are syncing in periods of months, there is no advantage in the 
wire formats.

There is no connection with the server.

A poll should consume data on any reasonable data billing system.

David Woolley <david@ex.djwhome.demon.invalid> wrote:
> There is no connection with the server.

> A poll should consume data on any reasonable data billing system.

Adding on a bit...

A cursory look at a packet trace suggests an NTPv4 poll (plain, no
encryption/whatnot) seems to be a 76 byte IP datagram - that is the
NTPv4 message (48 bytes) plus the 8 byte UDP header and a 20 byte IPv4
header.  Add another 14 bytes if it is transmitted on Ethernet - what
the link-layer header size(s) will be for cellular I don't know.

Armed with that, and knowledge of how many time sources will be
queried, combined with the aforementioned (snipped) 16 second to 20
minute polling interval should allow the OP to come-up with reasonable
upper and lower bounds for how much data will be seen by the billing
system in a month.

rick jones
-- 
the road to hell is paved with business decisions...
these opinions are mine, all mine; HPE might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hpe.com  but NOT BOTH...

On 2016-11-07, David Woolley <david@ex.djwhome.demon.invalid> wrote:
> On 07/11/16 22:02, E-Mail Sent to this address will be added to the 
> BlackLists wrote:
>> Gualtiero wrote:
>>> I am setting up a gsm unit with either a pool.ntp.org time server or a time..apple.com. I understand that the ntp has a complex algorithm for time syncing, but I was wondering if there was an ballmark sync interval to the server. Will the time server
>> sync occur at least once a month? or more than once in 6 months? And does anyone know if a time server connection will consume gprs data? I ask because sim cards expire without any use (6 months) and I'm left wondering if NTP time server syncs will
>> consume a noticeable enough amount of cellular data to keep the SIM card from being cancelled?
>>
>
> Syncs happen once every 16 seconds to 20 minutes.  If you are syncing on 
> periods of days, there is no point in using the full NTP protocol, and 
> if you are syncing in periods of months, there is no advantage in the 
> wire formats.
>
> There is no connection with the server.
>
> A poll should consume data on any reasonable data billing system.

The question is whether or not it consumes enough data to trigger the
ISPs "this phone has been used, so the counter should be reset" trigger.
That I have no idea of.

>