[ntp:questions] project ntp.br
François Meyer
nobody at nowhere.invalid
Fri Oct 5 11:42:09 UTC 2007
Antonio M. Moreiras <antonio at moreiras.eng.br> wrote:
> Dear Sirs:
>
> NIC.br is working on the project ntp.br, that has the goal of improving
> the quality of time synchronization in (brazilian) Internet hosts and
> networks and of provide legal brazilian time.
>
> Basically we intend to provide stratum 1 and stratum 2 servers,
> synchronized with legal brazilian time (that is kept by the observatorio
> nacional - www.on.br - and is, in last instance, UTC).
> We will have 3 of the following structure (at 3 different sites, at 3
> different cities: Sao Paulo, Rio de Janeiro, Brasilia):
>
> -----------------------------------------------------------
> Observatorio Nacional (Cesium clock)
> |
> |(periodically assures the
> | accuracy with the official
> | brazilian time - that is
> | in last instance UTC)
For real time purposes (as NTP), formally this is
UTC(ONRJ), TA(ONSP) and TA(ONBR) (just formal, no
practical consequences if only NTP is concerned).
> #
> ** Rubidium clock **
> ** Stratum 0 **
> Symmetrycom
I cant see why you need a Rb clock here if UTC(ONRJ)
(or a slightly degraded version in the case of the
secondary observatories) is available locally.
No remark on the structure below stratum 1, but from
a metrological point of view, in my opinion, the
complete structure could read like this :
UTC
|
|Circular T BIPM
|
|
UTC(ONRJ) ---------------> NTP st 1, id 0 ---> down to lower strata
| |
| peer
| |
|__________TA(ONSP) ---> NTP st 1, id 1---> down to lower strata
| GPS link |
| peer
| |
|__________TA(ONBR) ---> NTP st 1, id 2 ---> down to lower strata
GPS link
--
François Meyer
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