[ntp:hackers] Leap second list file

Mike S mikes at flatsurface.com
Mon Jan 16 12:03:51 UTC 2012


On 1/16/2012 3:02 AM, Dave Hart wrote:
> On Mon, Jan 16, 2012 at 02:30, Danny Mayer<mayer at ntp.org>  wrote:
>> On 1/15/2012 3:17 PM, Warner Losh wrote:
>>> Also, it is only 'leap second at the end of today' nor 'leap second at end of the month'
>>
>> No, that's not what it says. See below:
>>
>> LI Leap Indicator (leap): 2-bit integer warning of an impending leap
>>    second to be inserted or deleted in the last minute of the current
>>    month with values defined in Figure 9.
>
Given those two factors, I wonder if ntpd should be
> changed to indicate pending leap seconds earlier, perhaps after the
> first hour of the month to guard against accidentally misfiring the
> change a month early.

Since the only mention of LI timing in RFC 5905 refers to "current 
month," I'd think the reference implementation should act accordingly. 
Waiting until the last day (or last second, for that matter) may be 
pedantically correct, but since the purpose of the LI flag is to provide 
advance warning, that warning should be given as far in advance as 
practical. Since leap seconds can only occur on month boundaries, 
starting to announce LI shortly after the start of a relevant month is 
appropriate.


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