Ntp Servers And Peers - Spectracom VersaSync User Manual

2.7 Configuring Network Settings
5.
Click the Submit button.
2.7.8.8

NTP Servers and Peers

VersaSync can be configured to receive time from one or more available NTP Servers (Ver-
saSyncs or different models). This allows for NTP Servers on a timing network to be configured
as potential (fallback) input time references for VersaSync System Time synchronization. In the
event that a current reference becomes unavailable, VersaSync 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 Servers at a higher Stratum level, on the other hand, are called
net Time Servers should be configured as NTP Servers and not as NTP Peers).
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
other higher stratum servers. If a peer loses all reference clocks or fails, the other peers continue
to provide time to other clients on the network.
NTP Servers at the same Stratum level
86
Spectracom, however, recommends to
vice to use VersaSync's System Time during Holdover , i.e. if the external NTP ref-
erence has become unavailable.
Prefer Stratum 1
Uncheck this option to prevent VersaSync's NTP service from "weighing" the Tim-
ing System input heavier than input from other NTP servers. Thus, during normal
operation, the time provided by the external Stratum 1 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 Stratum 1 1PPS
this option to prevent NTP from using the 1PPS input from the Timing Sys-
Uncheck
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.
NTP Peers to each other.
IMPORTANT: In order for other NTP servers to be a valid reference, you
Note:
must enable "NTP" in the Reference Priority table (see "Configuring Input Refer-
ence Priorities" on page 131).
this box, thus allowing the NTP Ser-
check
NTP Servers
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2 VersaSync User Manual Rev. 6.0
(Note that Inter-