CLI Reference Guide-R05

Chapter 4 | System Management Commands
Synchronous Ethernet
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◆ The clock source port will not itself send out SSM. The other SSM-enabled ports
will only send out SSM if received on the clock source port. SSM will be sent out
of the other SSM-enabled ports once a second. If SSM has not been received on
the clock source port after five seconds, the other SSM-enabled ports will stop
sending SSM until a new clock source is selected.
◆ If SSM is disabled for a port, the priority level will be restored to the default
value.
Mode Changes
◆ The switch can only be configured to use SSM for dynamic clock source
selection when the current selection mode is set to Manual. The mode cannot
be changed directly from SSM mode to Auto mode, or from Auto mode to SSM
mode.
◆ If the switch is changed from SSM mode to Manual mode, and a port has been
chosen as the active clock source in SSM mode, this port will still be the active
clock source in Manual mode. If no clock source port has been selected in SSM
mode, the local clock will be used as the active clock source.
◆ If the switch is changed from Manual mode to SSM mode, and a port has been
chosen as the active clock source in Manual mode, this port will no longer be
the active clock source. All clock source ports configured under Manual mode
will be removed. The new active clock source is determined as described under
the first item in this section.
◆ If the switch is changed from Manual mode to SSM mode using the no form of
this command, and a port has been chosen as the active clock source in Auto
mode, this port will be the active clock source in Manual Mode. If there is no
active clock source in Auto mode, the local clock will be used as clock source in
Manual mode. All ports configured as clock source ports under Auto mode will
be kept after changing to Manual mode.
Link State Changes
◆ If an SSM-enabled port links up, the new active clock source is determined as
described under the first item in this section.
◆ If SSM-chose clock source port goes down, the switch will choose the next
clock source port as described under the first item in this section. If no other
port can be used as the clock source port, the local clock will be used as the
active clock source.
Joining a Trunk
◆ If an SSM-enabled port is added to a trunk, and the trunk is not operating at
1Gbps (full duplex), this port will no longer process SSM, and cannot be used a
clock source port.