Basic System Configuration Guide System Management
Edition: 01 3HE 11010 AAAC TQZZA 259
If an SFP that does not support synchronous Ethernet is installed, the Ethernet card
will use its local oscillator for transmit timing and an event is logged. If the Ethernet
port is configured as a source of node synchronization and an SFP that does not
support synchronous Ethernet is installed, a clock will not be supplied to the SSU and
an event is logged.
Each synchronous Ethernet port can be configured to recover received timing and
send it to the SSU. On the 7705 SAR-M, 7705 SAR-H, 7705 SAR-Hc, 7705 SAR-A,
7705 SAR-Ax, 7705 SAR-W, and 7705 SAR-Wx, any synchronous
Ethernet-capable port can be used as an available reference. In addition, two
references are available on the 7705 SAR-X, and on the 2-port 10GigE (Ethernet)
module or 6-port SAR-M Ethernet module when the modules are installed in the
7705 SAR-M (variants with module slot). On the 7705 SAR-8 and 7705 SAR-18:
• one reference is available on the 8-port Ethernet Adapter card, version 2
• two references are available on:
− the 6-port Ethernet 10Gbps Adapter card
− the 8-port Gigabit Ethernet Adapter card
− the 2-port 10GigE (Ethernet) Adapter card
− the 10-port 1GigE/1-port 10GigE X-Adapter card (not supported on the
7705 SAR-8)
− the Packet Microwave Adapter card
Synchronous Ethernet ports always use node timing from the SSU. Configuration of
one port automatically configures the other port.
If timing is recovered from a synchronous Ethernet port from an upstream non-
synchronous Ethernet free-running port and selected as the reference to the SSU,
then this clock may not be of sufficient quality or accuracy for node operations. This
reference may be disqualified because the frequency may not be within the pull-in
range of the SSU Stratum 3 oscillator.
On the 7705 SAR-M, 7705 SAR-Hc, 7705 SAR-A, 7705 SAR-Ax, 7705 SAR-W,
7705 SAR-Wx, 7705 SAR-X, and on the Packet Microwave Adapter card, a copper-
based, RJ-45 synchronous Ethernet port phy-tx-clock must be configured as slave
before the port is configured to be a timing source for the node. If a copper-based,
RJ-45 synchronous Ethernet port is a timing source for the node, the port phy-tx-
clock cannot be changed to another mode.
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