NTP Packet
n
Advance warning that a leap second adjustment will be made to the UTC timescale at the
end of the current day. Leap seconds are events mandated by the world time authority
(BIPM) in order to synchronize the UTC time scale with the earth's rotation.
n
Whether the NTP daemon is synchronized to a timing reference. The settings on the
NTP - Prefs
(on page 50) page affect LI behavior.
LI
Value
Meaning
00
0
No warning.
01
1
Leap second insertion: Last minute of the day has 61 seconds.
10
2
Leap second deletion: Last minute of the day has 59 seconds.
11
3
Alarm condition (Not synchronized)
When the SyncServer or NTP daemon is started or restarted, the leap indicator is set to "11",
the alarm condition. This alarm condition makes it possible for NTP clients to recognize that
an NTP server (the SyncServer) is present, but that it has yet to validate its time from its time
sources. Once the SyncServer finds a valid source of time and sets its clock, it sets the leap
indicator to an appropriate value. The
NTP Leap Change Alarm
on the
ADMIN - Alarms
page can be configured to generate an alarm and send notifications each time the leap indic-
ator changes state.
Version Number (VN)
This is a three-bit integer representing the NTP version number, currently 4.
Mode
This is a three-bit integer representing the mode, with values defined as follows:
Mode
Description
0
Reserved
1
Symmetric active
2
Symmetric passive
3
Client
4
Server
5
Broadcast
6
NTP control message
7
Reserved for private use
Stratum
This is an eight-bit integer that indicates the position of an NTP node within an NTP timing
hierarchy. It is calculated by adding 1 to the stratum of the NTP
system peer
.
For the SyncServer, the stratum values are defined as follows:
Stratum
Definition
0
Hardware Clock when locked.
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