Huawei Quidway S8500 Series Command Manual page 1051

Command Manual – System Management
Quidway S8500 Series Routing Switches
View
System view
Parameter
dnu: Should be used for synchronization (DNU).
lnc: G.812 local node clock signal (LNC).
prc:G.811 clock signal (PRC).
sets: Clock source signal of SDH equipment (SETS).
tnc: G.812 transfer node clock signal (TNC).
unknown: The quality of synchronization is unknown.
source: The number of clock source, ranging from 1 to 18.
Description
Use the clock ssm command to set the SSM level of each clock source:
For line clock source, the set SSM level is the SSM level of the clock source.
For Bits clock source, if the input signal is 2048kbit/s (E1) and SSM is engaged in
control, the SSM level of the clock source is the SSM level extracted from the input
signal, and the set SSM level is neglected.
For Bits clock source, if the input signal is 2048kHz signal, or the input signal is
2048kbits/s signal but SSM is not engaged in control, the set SSM level is the SSM
level of the clock source.
SSM means Synchronization Status Marker, which is also referred to as synchronous
quality information. It is used to indicate the level of synchronous timing signal in
synchronous timing transfer link. For line clock sources, SSM is extracted by the
interface card and reported to the SRPU, and then the SRPU sets the SSM of the line
clock source for the clock module.
When the clock module is powered on, the clock level of all clock sources is unknown.
From high to low, the order of SSM levels is: PRC > TNC > LNC > SETS > unknown >
DNU. If the SSM level of a clock source is DNU and SSM is engaged in control, the
clock source will not be selected during clock source switching.
The SRPU will notify the corresponding interface card about theSSM level after setting
the SSM level. If the SSM level of the line clock source can be extracted, the set SSM
level will be invalidated. Otherwise, the set SSM level will apply.
Example
# Set the SSM level of clock source 1 to DNU.
<Quidway> system-view
System View: return to User View with Ctrl+Z.
[Quidway] clock ssm dnu source 1
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4-9
Chapter 4 System Maintenance Commands