Item
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Description
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Timing Mode
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Sets the node timing mode:
External: The ONS node derives its timing from a building integrated timing
supply (BITS) source wired to the backplane pins.
Line: Timing is derived from an OC-N card or optical service channel (OSC)
card (in dense wavelength division multiplexing [DWDM] nodes) that is
optically connected to the timing node.
Mixed: Timing is set to external and line timing references.
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SSM Message Set
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Provisions the Synchronization Status Message (SSM) set. Generation 2 is used if the ONS node is connected to other ONS nodes. Generation 1 is used only when the ONS node is connected to equipment that does not support Generation 2. If a node that has its SSM Message Set set to Generation 1 receives a Generation 2 message, it maps the message down to the next available Generation 1 message. TNC and ST3E will become an ST3.
The Generation 1 message set includes RES, PRS (also called ST1), STU, ST2, ST3, SMC, ST4, and DUS. The Generation 2 message set adds transit node clock (TNC) and ST3E (following ST2).
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Quality of RES
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Provisions the timing quality for timing sources that support the reserved S1 byte. (Most timing sources do not use RES.) Qualities appear as ranges in descending quality order. For example, ST3<RES<ST2 means the timing reference is higher than a Stratum 3 and lower than a Stratum 2. Refer to the ONS product documentation for more information about SSM, including definitions of the SONET timing levels.
Revertive: If checked, the ONS node reverts to a primary reference source after
the conditions that caused it to switch to a secondary timing reference are
corrected.
Revertive Time: If Revertive is checked, indicates the amount of time the
ONS node will wait before reverting to its primary timing source. Five minutes
is the default.
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Reference Lists
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Defines the node's timing references (Ref 1, Ref 2, Ref 3). The node uses Reference 1 unless a failure occurs to that reference or its quality degrades, in which case the node uses Reference 2. If Reference 2 fails, the node uses Reference 3, which is typically set to Internal Clock (the Stratum 3 clock provided on the TCC2 card). The options that appear depend on the Timing Mode setting.
If the Timing Mode is set to External, options are BITS-1, BITS-2, and Internal
Clock.
If the Timing Mode is set to Line, options are the node's working OC-N cards
(non-DWDM nodes) or OSC cards (DWDM nodes) and Internal Clock.
If the Timing Mode is set to Mixed, both BITS and OC-N cards are available.
BITS-1 Out/BITS-2 Out: Sets the timing references for equipment connected
to the BITS Out backplane pins. BITS-1 Out and BITS-2 Out are enabled when
BITS-1 and BITS-2 facilities are put in service.
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Apply
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Applies changes to the Timing > General subtab.
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Reset
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Cancels Timing > General subtab changes and returns the fields to their last-saved settings.
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Help
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Displays context-sensitive help.
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