That page appears to be out-of-date. The current protocol, for NTP
version 4, is here: http://www.ietf.org/rfc/rfc5905.txt
Note that there was a change from the earlier version, which did say
"current day". Also, the LI ("Leap Indicator") field is only used to
indicate presence/absence of an impending leap second.
The current doc says in part:
The fields and associated packet variables (in parentheses) are
interpreted as follows:
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.
+-------+----------------------------------------+
| Value | Meaning |
+-------+----------------------------------------+
| 0 | no warning |
| 1 | last minute of the day has 61 seconds |
| 2 | last minute of the day has 59 seconds |
| 3 | unknown (clock unsynchronized) |
+-------+----------------------------------------+
Figure 9: Leap Indicator
Technically, there should be no need for the 2-week buffer I suggested.
However, it shouldn't hurt, and seems likely to add robustness. The
true correct solution would be to ensure that ntpd clients pay as much
attention to LI=00 from a server as to LI != 00 (and to fix the bug
Martin filed, in which the LI field goes to 00 in the last second BEFORE
the leap second - oops). Then they would be able to recover gracefully
from a brief persistence of the LI=01 value past the leap second -
assuming that no stratum 1 servers erroneously persisted the LI value.
We really need to understand why that is happening - do we have version
info from the servers that are still doing that?
Another suggestion... Should ntpd require that a stratum-1 server has a
non-expired leap-second file, and that that file should override any
upstream server for the LI data?
--Jeff
On 8/3/2012 11:48 AM, E-Mail Sent to this address will be added to the
BlackLists wrote:
Martin Burnicki wrote:
clients to independently set LI=00 during, say the first
half of the month, and to ignore the LI value from
servers during that time.
I think you would have to be more exact than that.
LI is used for more than one thing.
<http://www.eecis.udel.edu/~mills/ntp/html/decode.html>
According to the doc, LI only applies to the current day?
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