Note: Holdover and FOCA: As mentioned above FOCA only switches
between timing source when a failure is detected. This mean that if the act-
ive timing source of a device is HO, it will stick to it until reaching the
expired states (Failure state of HO).
Note: GNSS reference to discipline the HO: The holdover adaptative
algorithms have been optimized to learn from a GNSS reference clock
(GPS L1 signals). A better clock can be used as reference (e.g., Atomic
Clock, ePRTC, multi bands/constellations GNSS receiver) but using a clock
reference with worth performance might not fulfil the provided spe-
cifications.
5.7.1 Configuration
The configuration of the holdover is easy and can be leaved untouched. However, depend-
ing on the user needs and the boundaries for timing accuracy, the Time to expired value
should be adjusted to meet its specifications.
OID Name Value Type Description
3.7210.x holdover/cfg/xxx Configuration for the Holdover if avail-
able
3.7210.0 Source Rank <Integer>
Default: 0
Source rank of the holdover as timing source. If
leaved at zero it will be always placed as the last
timing source. Then the user can allow to trigger
the holdover between W
3.7210.1 Time to expire <Integer>
Default:
79800
Time until the holdover is considered out of spe-
cification and expired (default ~24h)
3.7210.2 Force Trigger <Enum>
0. STOP
1. START
2. NONE
Force to manually trigger the holdover (START) or
to expire it (STOP) without waiting the expiration
timer. NONE, does nothing.
Note: HO in between timing source: Using the source rank the HO can be
placed between two timing sources. For example, the user can use WR as
primary timing source, HO as secondary and PTP 8265.1 as third one. This
means that if WR fails, the device will enter in HO until expiration and finally
switch to PTP that might provide better accuracy than an expired HO.
5.7 Holdover
CHAPTER 5 • WR-Z16 User Manual Rev. v3.4
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