[aklug] Re: ntp and freebsd?

On 3/24/12 9:02 PM, Shane Spencer wrote:
> On Sat, Mar 24, 2012 at 1:51 PM, Christopher Brown <cbrown@woods.net> wrote=
> :
>> On 3/16/12 4:47 PM, Shane Spencer wrote:
>>> On Fri, Mar 16, 2012 at 3:45 PM, Leif Sawyer <lsawyer@gci.com> wrote:
>>>> GCI has stratum one time here in Anchorage and down in Seattle.
>>>>
>>>> ntp.gci.net =3DA0slaves off of it, so it's stratum-2 =3DA0 which is fin=
> e
>>>> for nearly everybuggy.
>>>>
>>>
>>> Sweet.. what makes up the Stratum 1 devices?
>>
>>
>> The most common source for a Stratum 1 NTP system is GPS.
>>
>>
>> At the base level, it could be a high end consumer type GPS units with
>> timing outputs (has a X PPS (pulse per second), usually 1PPS) to provide
>> interval, and serial output of time that can be identified accurately
>> against the pulse it applies to (there are a number of low end units
>> with 1PPS out but faulty Q/C in the design phase. =A0They output the data=
> ,
>> but you cannot accurately match serial fed time data with which pulse it
>> applied to). =A0Generally needs a good fixed external antenna with a clea=
> r
>> view to work well.
>>
>>
>
>
> Indeed. I wasn't sure if GPS was considered Stratum 1. I had to use
> USB GPS devices when working on machines that didn't have RTCs. I'd
> get the initial time sync then let NTP start up and start tuning
> during boot up.

It would generally be in good taste to downmark a verified generic GPS
source to stratum 2, and not even export a unverified generic GPS.
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Received on Sat Mar 24 23:14:27 2012