Cisco ONS 15310-MA SDH Procedure Manual page 352

Quality of RES—If your timing source supports the reserved S1 byte, set the timing quality here.
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(Most timing sources do not use RES.) Qualities are displayed in descending quality order as ranges.
For example, ST3<RES<ST2 means the timing reference is higher than a Stratum 3 and lower than
a Stratum 2. Refer to the "Timing" chapter in the Cisco ONS 15310-MA SDH Reference Manual for
more information about SSM, including definitions of the SDH timing levels.
Revertive—Check this check box if you want the ONS 15310-MA SDH to revert to a primary
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reference source after the conditions that caused it to switch to a secondary timing reference are
corrected.
Reversion Time—If Revertive is checked, choose the amount of time the ONS 15310-MA SDH will
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wait before reverting to its primary timing source. Five minutes is the default.
Step 3 In the Reference Lists area, complete the following information:
Note
NE Reference—Allows you to define three timing references (Ref 1, Ref 2, Ref 3). The node uses
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Reference 1 unless a failure occurs to that reference, 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 internal
clock is the Stratum 3 clock provided on the 15310E-CTX-K9. The options displayed depend on the
Timing Mode setting.
If the Timing Mode is set to External, your options are BITS1 and Internal Clock.
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If the Timing Mode is set to Line, your options are the 15310E-CTX-K9 and Internal Clock. Choose
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the port that is directly or indirectly connected to the node wired to the BITS source, that is, the BITS
port on the ONS 15310-MA SDH. Set Reference 1 to the port that is closest to the BITS source. For
example, if the E1 port is connected to the node wired to the BITS source, choose Slot 2 (CTX), Port
1 (E1) as Reference 1.
If the Timing Mode is set to Mixed, both BITS and the 15310E-CTX-K9 are available, allowing you
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to set a mixture of external BITS and the CTX as timing references.
BITS-1 Out—Define the timing references for equipment wired to the BITS Out connection on the
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15310E-CTX-K9. BITS-1 Out is enabled when BITS-1 facilities are put in service. If Timing Mode
is set to external, choose the port used to set the timing. If Timing Mode is set to Line, you can
choose a port or choose NE Reference to have the BITS-1 Out follow the same timing references as
the NE.
Click Apply.
Step 4
Note
In the node view, click the Provisioning > Timing > BITS Facilities tabs.
Step 5
In the BITS Facilities area, complete the following information:
Step 6
Note
Cisco ONS 15310-MA SDH Procedure Guide, Release 9.1 and Release 9.2
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You can define up to three timing references for the node and up to three BITS-1 Out references.
BITS-1 Out reference defines the timing reference used by equipment that can be attached to the
node's BITS Out connection. If you attach equipment to the BITS Out connection, you normally
attach it to a node with Line mode because equipment near the external timing reference can be
directly wired to the reference.
Refer to the Cisco ONS 15310-MA SDH Troubleshooting Guide for timing-related alarms.
The BITS Facilities section sets the parameters for your BITS1 timing references. Many of these
settings are determined by the timing source manufacturer. If equipment is timed through BITS
Out, you can set timing parameters to meet the requirements of the equipment.
Chapter 16 DLPs H1 to H99
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