ECS4660-28F_Management Guide-R03

C HAPTER 24 | System Management Commands
Synchronous Ethernet
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synce ethernet
clock-source
This command manually sets a port as a clock source, or as a candidate
clock source at the specified priority when using automatic clock source
selection. Use the no form to remove a port as a clock source.
SYNTAX
synce ethernet unit/port clock-source [priority priority]
no synce synce ethernet unit/port clock-source
unit - Unit identifier. (Range: 1)
port - Port number. (Range: 1-28)
priority - The priority used by automatic clock source selection.
(Range: 1-65535)
DEFAULT SETTING
Disabled
COMMAND MODE
Global Configuration
COMMAND USAGE
◆ This command can enable SyncE on trunk member but not on a trunk.
◆ If more than one port is configured as clock source port with this
command, the first configured port will be set as the active clock source
port.
◆ If an active clock source port is removed as the clock source, no active
clock source port will exist until explicitly configured.
◆ When no active clock-source port exists, the switch’s internal clock will
be used as the clock source.
◆ If the priority of the clock-source port is not specified, the port ID of the
clock-source port will be used as the priority for automatic clock source
selection (see the synce auto-clock-source-selecting command).
◆ Lower priority values indicate higher precedence. If more than two
clock-source ports have the same priority value, the clock source-port
with the lowest port ID assumes higher precedence.
◆ If SyncE has locked the clock source and the clock source becomes
invalid, SyncE will operate in holdover mode, switching over to the local
reference clock if all available clock source signals fail. If SyncE has
never locked the clock source and no valid clock source exists, SyncE
will operate in free-run mode. If SyncE locked the clock source, SyncE
will operate in locked mode.
Note that a clock is said to be in holdover mode if it was previously
synchronized to another clock (normally the primary reference clock)
but is now free-running on its own internal oscillator, whose frequency
is being adjusted using data acquired while it had been synchronized to
the other clock.