Working Mode Of The Clock Monitoring Module Of The Srpu; Working Mode Of The Port Clock - H3C S9500 Series Operation Manual

Operation Manual – Clock Monitoring
H3C S9500 Series Routing Switches
DNU: DoNotUse
The reference source whose SSM level is DNU cannot be used as a clock source.

1.1.4 Working Mode of the Clock Monitoring Module of the SRPU

The working mode of the clock monitoring module is also the mode it adopts to choose
the clock source, including the manual mode and the auto mode.
I. Manual mode
In this mode, the clock source is configured manually. The clock monitoring module
does not switch the clock source automatically, but just tracks the user-configured
primary reference source. If the primary reference source is lost, the clock monitoring
module enters a hold state.
II. Auto mode
In auto mode, the clock source is selected by the system automatically. When the
primary clock source is lost or in free run status, the clock monitoring module selects
another clock source based on the following rules:
If SSM level is not activated, the clock source is decided by reference source
priority. If two reference sources have the same priority, the one with the smaller
reference source number (1 to 18) is selected. When the reference source with the
highest priority is missing, the next available reference source with the highest
priority is selected. When the former clock source becomes available, the system
switches to that clock again.
If SSM is activated, the clock source is decided by the SSM level. If two reference
sources have the same SSM level, the reference source priority takes effect, in the
way described above.
Note:
The following clock sources are excluded in clock selection (when SSM is activated):
Clock sources whose signals are missing;
Clock sources whose priority is 255. By default, the priority of all clock sources is
255.
Clock sources whose SSM level is DNU (DoNotUse).

1.1.5 Working Mode of the Port Clock

Depending on the source of the port clock, a port of an S9500 series switch supports
two clock modes:
Chapter 1 Clock Monitoring Configuration
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