4.
Check the first of the three options, and uncheck the latter two:
Enable Stratum 1 Operation
When the checkbox Prefer Stratum1 is unchecked, the input from a different NTP
Server or Peer will normally be used at all times.
Spectracom, however, recommends to check this box, thus allowing the NTP Ser
vice to use NetClock's System Time during Holdover, i.e. if the external NTP ref
erence has become unavailable.
Prefer Stratum1
Uncheck this option to prevent NetClock's NTP service from “weighing” the Timing
System input heavier than input from other NTP servers. Thus, during normal oper
ation, the time provided by the external Stratum1 NTP server will be used (unless
its quality is determined to be low).
Note: If enabled, this function would give GPS additional “weight”
for NTP to select the GNSS input over other NTP Servers.
Enable Stratum1 1PPS
Uncheck this option to prevent NTP from using the 1PPS input from the Timing Sys
tem, but instead use the 1PPS signal from another NTP server. This will ensure the
time signal and the 1PPS signal to correlate, which tends to result in better NTP
performance.
5.
Click the Submit button.
2.15.8 NTP Servers and Peers
NetClock can be configured to receive time from one or more available NTP Servers (NetC
locks or different models). This allows for NTP Servers on a timing network to be configured as
potential (fallback) input time references for NetClock System Time synchronization. In the event
that a current reference becomes unavailable, NetClock can fallback to the other NTP Servers
available on the network.
A group of NTP servers at the same Stratum level (Stratum 1 time servers, for example) are con
sidered as NTP Peers to each other.
NTP Servers at a higher Stratum level, on the other hand, are called NTP Servers (Note that Inter
net Time Servers should be configured as NTP Servers and not as NTP Peers).
Note: IMPORTANT: In order for other NTP servers to be a valid reference, you
must enable “NTP” in the Reference Priority table (see "Configuring Input Refer
ence Priorities" on page163).
For mutual fallback purposes, it is recommended to use one or more NTP Peers. Each peer is
normally configured to operate from one or more time sources including reference clocks or
2.15 Configuring NTP
CHAPTER 2 • NetClock User Reference Guide Rev. 16
105