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Chapter 3
Cisco CMTS Show Commands
Table 3-45 show controllers cable upstream Command Field Descriptions (continued)
Field
<card-name> CNR measurement Estimate for the overall carrier-to-noise ratio (CNR) for the
Nominal Input Power level
Tx Timing Offset
Ranging Backoff Start/End
Ranging Backoff Automatic
Tx Backoff Start
Tx Backoff End
Modulation Profile Group
part_id=
rev_id=
rev2_id=
nb_agc_thr=
nb_agc_nom=
Range Load Reg Size=
Request Load Reg Size=
Minislot Size in number of
Timebase Ticks is
Minislot Size in Symbols
Bandwidth Requests
Piggyback Requests
OL-1581-08
Description
upstream for cable interfaces that include onboard hardware-based
spectrum management (such as the Cisco uBR-MC16S or
Cisco uBR-MC5X20S). When the CNR measurement exceeds
40 dB, this line states "better than 40 dB." As a general rule, the
CNR is greater than the SNR value.
Note
This value is only an estimate—for the most accurate
value, use a spectrum analyzer or use the
cable upstream spectrum
modems, you can also use the
command.
Indicates the desired power level coming into the receiver.
Indicates the largest ranging offset reported by CMs on the
upstream.
Indicates how many ranging slots (expressed as an exponent of 2)
to back off before resending the ranging bursts after an upstream
collision. These values are configured using the cable upstream
range-backoff start end command.
Start and End Ranging Backoff exponents, which are set
automatically, using the cable upstream range-backoff
automatic command.
These counters are not accurately updated on the
Note
Cisco uBR-MC5X20S cable interface line card, which
should manually configure ranging backoff instead.
Indicates the starting exponential backoff value for data collisions.
Indicates the ending exponential backoff value for data collisions.
A set of burst profiles defining an upstream range.
The part number of the PHY chip. FFFF means the PHY chip is
turned off.
The PHY chip revision number.
The PHY chip subrevision number.
Threshold used to control gain.
Used to accelerate convergence of input power level.
Size, indicated by number of symbols, for range request bursts.
Size, indicated by number of symbols, for request bursts.
Size in tick units of upstream minislot. A tick is 6.25 microseconds.
Size in symbols of the upstream minislot.
Number of successful bandwidth requests received in the
contention minislots.
Number of successful bandwidth requests piggybacked with
regular data transmissions.
Cisco Broadband Cable Command Reference Guide
show controllers cable
show controllers
command. For individual cable
show cable modem cnr
3-173
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