Alcatel-Lucent 7450 Basic System Configuration Manual page 404

System Command Reference
Description The synchronous equipment timing subsystem can lock to different timing reference inputs, those
specified in the ref1, ref2, bits and ptp (ptp applies only to the 7450 ESS and 7750 SR) command
configuration. This command organizes the priority order of the timing references.
If a reference source is disabled, then the clock from the next reference source as defined by ref-order
is used. If all reference sources are disabled, then clocking is derived from a local oscillator.
If a sync-if-timing reference is linked to a source port that is operationally down, the port is no longer
qualified as a valid reference.
For 7450 ESS and 7750 SR systems with two SF/CPM modules, the system distinguishes between the
BITS inputs on the active and standby CPMs. The active CPM will use its BITS input port providing
that port is qualified. If the local port is not qualified, then the active CPM will use the BITS input port
from the standby CPM as the next priority reference. For example, the normal ref-order of bits ref1
ref2 will actually be bits (active CPM), followed by bits (standby CPM), followed by ref1, followed
by ref2.
For 7750 SR-c4 systems, the system distinguishes between the two BITS inputs on the CFM. The CFM
will use its BITS input port bits1 providing that port is qualified. If port bits1 is not qualified, then the
CFM will use the BITS input port bits2 as the next priority reference. For example, the normal ref-
order of bits ref1 ref2 will actually be bits1 followed by bits2, followed by ref1, followed by ref2.
For 7950 XRS systems with two SF/CPMs and two CCMs, the system distinguishes between the BITS
inputs on the CCMs associated with the active and standby CPMs. The active CPM will use the BITS
input port on the associated CCM, provided that the port is qualified. If the local port is not qualified,
then the active CPM will use the BITS input port from the CCM associated with the standby CPM as
the next priority reference. For example, the normal ref-order of bits ref1 ref2 will actually be bits
(active CCM), followed by bits (standby CCM), followed by ref1, followed by ref2.
The no form of the command resets the reference order to the default values.
The bits option is not supported on the 7750 SR-c12 chassis.
Default bits ref1 ref2 ptp (7750 SR and 7450 ESS)
bits ref1 ref2 (7950 XRS)
Parameters
first — Specifies the first timing reference to use in the reference order sequence.
second — Specifies the second timing reference to use in the reference order sequence.
third — Specifies the third timing reference to use in the reference order sequence.
ref1
Syntax ref1
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Values
ref1, ref2, bits, ptp
Values
ref1, ref2, bits, ptp
Values
ref1, ref2, bits, ptp
Basic System Configuration Guide