098-00720-000 Revision D1 – February, 2018 SyncServer 600 Series User’s Guide 103
Chapter 4
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The SyncServer S6x0 supports both broadcast and multicast.
Prefer The NTP daemon will synchronize with an association marked prefer over an
equivalent association that is not. The internal hardware reference clock prefer
setting can be cleared in order to allow an external NTP server to be preferred
over the internal hardware reference clock.
By default the SyncServer S600 Series has the NTP Prefer selected for the local
hardware reference clock. In most operating scenarios the local hardware
reference clock (which more often than not will be tracking GNSS) will be the only
reference being used. With the Prefer being selected, and no statistically better
reference available, the time server will achieve Stratum 1 status on startup or
restart as rapidly as possible. If the Prefer is not selected for the hardware
reference clock then the NTP daemon will go through a standard validation
procedure for a reference clock. This procedure will take several minutes and
should happen by the time the reach indicates 377 on the reference clock
association. For optimal operation, Microsemi recommends the local hardware
reference remain selected as a Prefer in the configuration.
Burst Burst
When the server is reachable, send a burst of eight packets instead of the usual
one. The packet spacing is about two seconds. This is designed to improve
timekeeping quality for server associations. This setting should only be used in
agreement with the administrator of the remote NTP device as the traffic load
may be onerous.
iBurst
When the server is unreachable, send a burst of eight packets instead of the
usual one. As long as the server is unreachable, the packet spacing is about 16s
to allow a modem call to complete. Once the server is reachable, the packet
spacing is about two seconds. This is designed to speed the initial
synchronization acquisition with the server command.
MinPoll This option specifies the minimum poll interval for NTP messages, in seconds to
the power of two. The minimum poll interval defaults to 6 (64 s), but can be
decreased to a lower limit of 4 (16 s).
MaxPoll This option specifies the maximum poll interval for NTP messages, in seconds to
the power of two. The maximum poll interval defaults to 10 (1,024 s), but can be
increased to an upper limit of 17 (36.4 h).
Symmetric This option specifies an optional MD5 symmetric key ID, which must be 20
characters.
Restart After changing the NTP configuration, click the RESTART button to put the new
configuration into effect. While the NTP daemon restarts, its services are
temporarily unavailable, and it generates the following alarm events: NTP
Stratum Change, NTP System Peer Change, NTP Leap Change.
Table 4-7. NTPd Association Configuration Parameters (Continued)
Parameter Description
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